Org. Divers. Evol. 6, Electr. Suppl. 16, part 1: 1 - 82 (2006) © Gesellschaft für Biologische Systematik http://senckenberg.de/odes/06-16.htm URN: urn:nbn:de:0028-odes0616-5

Org. Divers. Evol. 6, Electr. Suppl. 16, part 1 (2006)

Malchus, N. & Pons, J.M. (eds) International Congress on Bivalvia: Abstracts. Electr. Suppl. 16, part 1. − to: Malchus, N. & Pons, J.M. (2006): Abstracts and Posters of the “International Congress on Bivalvia” at the Universitat Autònoma de Barcelona, Spain, 22-27 July 2006. Org. Divers. Evol. 6(4): 327.

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Preface Large congresses on Molluscan research tend to dilute bivalve-related themes while specific bivalve-meetings are non-periodic, almost “spontaneous” events. The principle aim of this year’s “International Congress on Bivalvia” was therefore to provide an adequate space for bivalve specialists (biologists and paleontologists) to present and discuss their most recent results on any aspect of bivalve-related research. The congress was organised by the ‘‘Departament de Geologia (Paleontologia)’’ with the collaboration of the ‘‘Museu de Ciencies Naturals’’ of Barcelona, ‘‘Institut de Recerca i Tecnologia Agroalimentàries’’, and the ‘‘Museo de Ciencias’’ (CosmoCaixa – obra social). It was inaugurated by Dr. Montserrat Pallarès, vice-rector for research at the UAB, Dr. Esteve Cardellach, head of the Geology Department, and the organisers Drs. Nikolaus Malchus and Jose Maria Pons.

A hundred and twenty three colleagues from 26 countries attended the meeting including 41 PhD students and the organising team of 20 colleagues and volunteering students from the Paleontology Unit of the UAB and from external institutions. Authors presented a wide range of biological and palaeontological themes featuring especially (i) population genetics and molecular phylogenetics, (ii) evolution of ontogeny, (iii) ecology and conservational biology of endangered freshwater bivalves, and (iv) evolutionary palaeontology. These topics were introduced by five keynote lectures: ‘‘The unusual system of mitochondrial inheritance in bivalves’’ by Eleftherios Zouros, ‘‘Evolution of molluscan ontogeny’’ by Gerhard Haszprunar, ‘‘Restauration of endangered freshwater bivalves in the United States’’ by Richard Neves, ‘‘Biomineralization of nacre in molluscs’’ by Antonio Checa, and ‘‘Paleontological perspectives on early bivalve evolution’’ by Joseph Carter. Complementary topics included biodiversity and classification, marine ecology and palaeoecology, and aquaculture and diseases.

The presentations covered all major bivalve clades providing many new evo-devo data, descriptions of new techniques (DNA extraction and amplification; monitoring of valve movements), computer-based analyses of (palaeo)geographic distributions, biodiversity and extinctions, analysis of shell micro- and ultrastructures, shell geochemistry and stable isotopes, geometric morphometrics, or rudist biostratigraphy and taxonomy, to name just some. Two scientific excursions were organised, one to the lower Ebro river and its delta (guided by Cristian Altaba), the other to Cretaceous carbonate platforms in the Pyrenees with build-ups of now extinct rudist bivalves (guided by Jose Maria Pons and Enric Vicens). In addition, the congress hosted the signal session for the multi-author endeavour to revise “The Treatise on Invertebrate Paleontology, part Bivalvia”, coordinated by Joe Carter and Roger Thomas. The participants could visit the new Museo de Ciencias of CosmoCaixa and the Museu de Ciencies Naturals (historical Zoology and Geology buildings) in Barcelona.

This supplement contains the abstracts of all 130 contributions, and we include 52 (of the 69) posters as well as the two field guides. Abstracts submitted for the congress had been reviewed by us and by Carlos Saavedra (genetics).and where this appeared necessary, were accepted after modifications. They are published here as edited for the congress incorporating corrections as provided by the authors after the congress. We had deliberately allowed for a slightly extended length of 350 words so that objectives, methods, brief discussion, and references could be included. This abstract type is much more informative than required for article abstracts. Abstracts which are complemented by a poster are essentially research notes. All posters included here have been checked for legibility, minimum quality of photos and figures, printability, and functioning of the links within the supplement. Given the inherent problems of reduction from poster size and difference of formats, this was not always an easy task. We hope to have achieved an acceptable quality for all of them. We would like to thank the editors for offering this type of publication and the contributors for their patience. Enric Vicens helped formatting the pdfs.

In the following you will find the welcome note of the original congress volume followed by the list of contributions subsumed according to topics. Posters are linked in the abstracts themselves. A list of all authors is given at the end of this volume.

N. Malchus and J. M. Pons

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Welcome In the name of the organising committee, we welcome you to the International Congress on Bivalvia, which is actually the seventh in a series of non-periodic bivalve meetings since 1977. Although the Bivalvia have always been in the focus of biological and palaeontogical research, the use of ever more powerful computers and more sophisticated technologies in the past years has lead to a substantial increase in our knowledge, quantitatively and qualitatively. The present event therefore owes itself to your interest in a scientific review and new synthesis as well as to the important role of bivalve molluscs in aquatic environments and their socio-economic importance.

Scientific meetings can hardly reflect all research fields in a comprehensive way. Nevertheless, thanks to your contributions of 56 given talks and 69 posters, this meeting comprises a wide spectrum of original research results on population genetics, molecular phylogenetics, ontogeny, evolutionary palaeontology, taxonomy, aquaculture, freshwater conservational biology, and last not least marine and freshwater biodiversity, ecology and palaeoecology. Besides, the congress offers five keynotes on three “hot” topics - “population genetics”, “evolution”, and “conservation of freshwater bivalves” - and the first planning session for a complete review of the bivalve volumes of the “Treatise on Invertebrate Paleontology” which resists unchanged for more than 35 years. We hope the meeting satisfies your scientific expectations and leaves some spare time for your cultural interests. In this sense, we wish you a stimulating and enjoyable stay at our university and in Barcelona.

This congress would not have been possible without the financial and logistic support of a number of organisations and institutions: Dirección General de Investigación, Ministerio de Educación y Ciencia; Agència de Gestió d’Ajuts Universitaris i de Recerca, Departament d’Universitats, Recerca i Societat de la Informació (Grup de recerca del Cretaci i Terciari inferior); Consejo Superior de Investigaciones Científicas (Museo Nacional de Ciencias Naturales); Vicerectorat d’Investigació, Universitat Autònoma de Barcelona; Promoció de Ciutat, Ajuntament de Cerdanyola del Vallès; Institut de Recerca i Tecnología Agroalimentàries; Institut de Cultura de l’Ajuntament de Barcelona (Museu de Ciències Naturals); Obra Social Fundació La Caixa (CosmoCaixa); Sociedad Española de Malacología (Emilio Rolán, Jesús Troncoso, José Templado); Società Italiana de Malacologia (Paolo Crovato); Agència de Promoció d’Activitats i de Congresos, Fundació UAB (Meritxell Navarro); and Sant Cugat Tours (Irene Roca).

Organisation of the field trip to the Ebro River and Delta, by Cristian Altaba and Miquel Àngel López, benefited from logistic support of Parc Natural de l’Ebre, Consell Comarcal del Montsià, and the non-governmental organisation Grup de Natura Freixe.

Our student assistants Javier Aguilar, Sergi Albrich, Sandra Córcoles, Moritz Malchus, Ramón Mercedes, Josep Anton Moreno, Angélica Oviedo, Yolanda Pichardo, Mònica Soler, Luis Troya, Vicent Vicedo, Raquel Villalonga, and Sheila Villalba greatly helped us to solve any practical aspect of the organisation. The realisation of the congress would have simply been impossible without their enthusiastic assistance.

A great “Thank you” to all of them.

Nikolaus Malchus and Jose Maria Pons

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Organising Committee Dr. Cristian Altaba, Universitat de les Illes Balears

Dr. Jaume Gallemí, Museu de Geologia (MCNC), Barcelona Dr. Eulalia Gili, Universitat Autònoma de Barcelona

Dr. Gregori López, Museu de Geologia (MCNC), Barcelona Dr. Nikolaus Malchus, Universitat Autònoma de Barcelona, (president)

Dr. Ricard Martínez, Universitat Autònoma de Barcelona Dr. Jose Maria Pons, Universitat Autònoma de Barcelona, (vice-president)

Dr. Carlos Saavedra, Instituto de Acuicultura-Torre La Sal, Castellón (CSIC) Dr. José Templado, Museo Nacional de Ciencias Naturales, Madrid (CSIC)

Dr. Francesc Uribe, Museu de Zoologia (MCNC), Barcelona Dr. Enric Vicens, Universitat Autònoma de Barcelona

Technical Assistance Javier Aguilar, Sergi Albrich, Sandra Córcoles, Moritz Malchus, Ramón Mercedes,

Josep Anton Moreno, Angélica Oviedo, Yolanda Pichardo, Mònica Soler, Luis Troya, Vicent Vicedo, Raquel Villalonga, Sheila Villalba

Scientific Committee Dr. Rudiger Bieler, The Field Museum, Chicago, USA

Dr. David Campbell, University of Alabama, USA Dr. Joseph Carter, University of North Carolina, USA

Dr. Antonio Checa, Universidad de Granada Dr. Graciela Delvene, Museo Geominero, Madrid

Dr. Gonzalo Giribet, Harvard University, USA Dr. Serge Gofas, Universidad de Málaga

Dr. Elizabeth Harper, Cambridge University, UK Dr. Gerhard Haszprunar, Zoologische Staatssammlung München, Germany

Dr. Katrin Linse, British Antarctic Survey, Cambridge, UK Dr. Paula Mikkelsen, American Museum of Natural History, NY, USA

Dr. Diarmaid Ó Foighil, Museum of Zoology, University of Michigan, USA Dr. Juan Peña, Instituto de Acuicultura Torre la Sal, Castellón (CSIC)

Dr. Carmen Salas, Universidad de Málaga Dr. Eleftherios Zouros, University of Crete, Greece

Sponsors and Collaborators

Logo and cover design: Vicent Vicedo

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Abstracts of Keynotes, Talks and Posters

Population Genetics Keynote

Eleftherios Zouros: The unusual system of mitochondrial inheritance in Bivalves p. 79

Talks

Glavinic, Ana; Rouse, Greg; Benckendorff, Kirsten: Species delimitation and phylogeography of Neotrigonia sp. in southern Australian seas 37Gosling, Elizabeth; Coghlan, Brian: A molecular approach to the study of a mussel (Mytilus) hybrid zone on the west coast of Ireland 38Knapp, Martina; Dreyer, Hermann; Steiner, Gerhard: The mitochondrial genomes of three European Limidae. High rearrangement rates on genus level and intraspecific differences

45

Okimoto, Takane; Aranishi, Futoshi: Genetic relationships among Japanese and Korean populations of cultured pacific oyster 59Passamonti, Marco: An unusual case of gender-associated mitochondrial DNA heteroplasmy: the mytilid Musculista senhousia (Mollusca: Bivalvia) 59Presa, Pablo; Llavona, Angela; Pérez, Montserrat; Seoane, Angela; Lado-Insua, Tania; Diz, Angel: Is the inter-annual rising of allelic richness in natural populations of Mytilus galloprovincialis related to the Prestige oil spill? 61Saavedra, Carlos: Genomic tools for population biology studies in clams and scallops 66

Posters

Carstensen, Daniel; Herrmann, Marko; Laudien, Jürgen; Schiel, Siegrid; Arntz, Wolf; Leese, Florian; Held, Christoph: Genetic variability of Chilean and Peruvian surfclams (Donax marincovichi and Donax obesulus) 20Diz, Angel; Presa, Pablo: Genetic structuring of Mytilus galloprovincialis at Iberian coasts 25Doherty, Sandra D.; Brophy, Deirdre; Gosling, Elizabeth: Gametogenic cycle of Mytilus in Galway bay 26Fernández-Moreno, Mercedes; Martínez-Lage, Andrés; Méndez Felpeto, Josefina; González-Tizón, Ana: Analysis of 16S rRNA and 12S rRNA mitochondrial genes in different European localities of Aequipecten opercularis 31Francisco-Candeira, Marta; Varela, Miguel; González-Tizón, Ana; Martínez-Lage, Andrés: Isolation and characterization of polymorphic microsatellite loci in the razor clam Solen marginatus 32Gudimov, Alexander V.: Permanent adaptation and speciation 39Knapp, Martina; Dreyer, Hermann; Steiner, Gerhard: The mitochondrial genomes of three European Limidae. High rearrangement rates on genus level and intraspecific differences 45Llavona, Angela; Presa, Pablo; Guiñez, Ricardo; Astorga, Marcela; Toro, Jorge; Pérez, Montserrat: New microsatellite markers for the ecosystem engineer Perumytilus purpuratus 50Silva-Hurtado, Ninoska; Morán, Paloma; Pasantes, Juan José: Genetic evidence of natural hybridization between Ruditapes decussatus and R. phillipinarum 70Silva-Hurtado, Ninoska; Morán, Paloma; Pasantes, Juan José: Sequence analysis of the

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ribosomal gene repeats of some bivalve species p. 70Yashiki, Ayako; Imai, Hideyuki; Yamaguchi, Masashi: Inter- and intraspecific genetic variability in the venerid bivalve, Meretrix spp. in the Western Pacific and Indian Ocean 77

Molecular Phylogenetics

Talks

Campbell, David C.: Implication of molecular data for unionoid generic nomenclature 19Crowley, Louise: Phylogenetic relationships of the Arcoida 23Giribet, Gonzalo: A multi-locus approach to bivalve phylogeny 37Kraffe, Edouard; Grall, Jacques; Leduff, Michel; Guderley, Helga; Marty, Yanic: Fatty acid compositions of cardiolipin in marine mollusk bivalves - phylogenetic occurrence and functional significance 47Lee, Taehwan: A comprehensive phylogeny of the holarctic Sphaeriinae (Veneroida, Sphaeriidae): systematics and genome amplification 48Lee, Taehwan; O´Foighil, Diarmaid: Placing the Floridian marine genetic disjunction into a regional evolutionary context using the Brachydontes exustus species complex

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Machordom, A.; Araujo, R.; Nagel, K. O.; Reis, Joaquim; Toledo, C.: A preliminary phylogeny of European Unionoidea 53Mikkelsen, Paula M.; Bieler, Rüdiger; Kappner, Isabella; Rawlings, Timothy A.: Phylogeny of Veneroidea (Heterodonta) based on morphology and molecules 56Steiner, Gerhard; Dreyer, Hermann; Knapp, Martina: What can mitochondrial genomics do for bivalve phylogeny? 73Taylor, John; Williams, Suzanne; Glover, Emily; Dyal, Patricia: Relationships of heterodont bivalves: new molecular data for 46 families. Out with the old in with the new? 74

Posters

Aranishi, Futoshi; Okimoto, Takane: Simple and chemical DNA extraction from preserved bivalve mantle for reproducible PCR amplification 16Kappner, Isabella; Bieler, Rüdiger: Phylogenetic studies of the marine bivalve Subfamily Venerinae 44Saavedra, Carlos; Peña, Juan: Phylogenetics of Pecten scallops based on 3 mitochondrial genes 66Steiner, Gerhard; Dreyer, Hermann; Knapp, Martina: Nucleotide substitution strand bias and control region orientation in bivalve mitochondrial genomes 73

Evolution of Ontogeny and Anatomy

Keynote

Gerhard Haszprunar: Evolution of molluscan ontogeny 41

Talks

Checa, Antonio G.; Esteban-Delgado, Francisco José; Salas, Carmen: Microridges in the inner dorsal shell of pectinids 22

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García-March, José Rafael; Márquez-Aliaga, Ana: Polymorphism and shell reshaping in Pinna nobilis L., 1758: the reliability of shell dimensions for ontogenetic age and population growth rate estimates p. 34Malchus, Nikolaus: The bivalve tooth puzzle: non?-homology of hinge teeth and dent-like structures 54Rogalla, Nicole S.; Amler, Michael: Morphology of hippocardiid and pseudobigaleaid (Rostroconchia) larval shells and their subsequent growth 65Sartori, André Fernando: Armoured siphons in laternulids (Anomalodesmata) 68Sha, Jingeng: Ontogenetic variations of the Early Cretaceous non-marine bivalve Trigonioides (T.) heilongjiangensis and their phylogenetic significance 69Stanton, Samuel Andrew: Ontogeny of ciliation of velum rim and mantle folds in veliger larvae of Crassostrea gigas 72Zanatta, David Thomas; Murphy, Robert: Evolution of active host-attraction strategies in the freshwater mussel tribe Lampsilini (Bivalvia: Unionidae) 78

Posters

Evseev, George A.; Kolotukhina, Natalya K.; Semenikhina, Olga Ya: Early ontogenetic features of Mytilus trossulus and Crenomytilus grayanus (Bivalvia: Mytilidae) and their usefulness for the mytilid taxonomy 30Herrmann, Marko; Giménez, Juliana; Laudien, Jürgen; Penchaszadeh, Pablo E.: Spermatozoa morphology and development of the surf clam Donax hanleyanus (Bivalvia: Donacidae) from Argentina 43López, Gregori: First evidences of a major radial fold in the inoceramid (Bivalvia) shell 50Malchus, Nikolaus: Easy to see, difficult to describe: towards a standardised description of bivalve larval shell shape 53Rogalla, Nicole S.; Amler, Michael: New terminology of rostroconch morphology 64Salas, Carmen; Pablo, Marina; Checa, Antonio G.: The periostracum of Digitaria digitaria (Bivalvia: Astartidae): formation and structure 67Signorelli, Javier Hernán; Pastorino, Guido: Anatomy and functional morphology of the southwestern Atlantic bivalve Mactra isabelleana d'Orbigny, 1846 (Heterodonta: Mactridae) 70

Biomineralization and Shell Microstructure

Keynote

Antonio G. Checa: Biomineralisation of nacre in molluscs 21

Talks

Esteban-Delgado, Francisco José; Checa, Antonio G.; Harper, Elizabeth Mary; Rodríguez-Navarro, Alejandro Basilio: Ultrastructural relationship between prismatic and foliated layers in some pteriomorph bivalves 29

Posters

Génio, Luciana; Kiel, Steffen; Little, Crispin Thomas Stephen; Grahame, John; Cunha, Marina Ribeiro: Shell microstructure of mytiloids (Bivalvia) 35Malchus, Nikolaus; Haggart James W.; Puhfal, Peir K.; Tozer, Edward T.; Orchard Michael J.; Nixon, G.: First evidence of a calcitic folio-prismatic palaeolophid "oyster" from

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the Norian of Wrangellia terrane, western Canada p. 55

Morphological Phylogeny, Classification and Taxonomy

Keynote

Joseph G. Carter: Morphological phylogenetics of the early Bivalvia 20

Talks

Barry, Peter James; McCormack, Grace: Is there a case for the Subfamily Axinopsidinae? : Revising the taxonomy of the minute thyasirids of the genera Adontorhina, Mendicula, Leptaxinus and Axinulus 17Fang, Zong-jie: A new scenario for the early evolution of the Bivalvia 30Kappner, Isabella: Geometric morphometrics of convergent species pairs of the subfamilies Venerinae and Chioninae 44Oliver, Graham: Morphological basis to systematics of Thyasiridae 59Pons, Jose Maria; Vicens, Enric: State of the art and proposals for a revised classification of radiolitid rudist bivalves 60Skelton, Peter William: Proposals for a revised classification of rudist bivalves 71Tëmkin, Ilya: Overcoming incongruence in the phylogeny of the Pterioidea 74Yancey, Thomas; Wilson, Mark: Alatoform edgewise reclining bivalves appear early in the Triassic 76Yancey, Thomas; Woods, Mark: Late Triassic wallowaconchid bivalves (megalodontoids) of the United Arab Emirates: functional wing design on large bivalves for alatoform edgewise reclining life habit 77

Posters

Aguilar, Javier: Immanitas Palmer is an Albian-Cenomanian Antillocaprinidae (Bivalvia, Hippuritoidea) 14Chiki-Aouimeur, Fettouma; Abdallah, Hassen; Pons, Jose Maria; Vicens, Enric: Rudists from the Cenomanian-Turonian of the Gafsa region, Tunisia 23El Hedeny, Magdy Mohamed: New systematic and biostratigraphic data on the Cenomanian-Turonian Radiolitidae (Bivalvia: Hippuritoidea) of Abu Roash, Western Desert, Egypt 29Machado, Deusana Maria da Costa: Systematic revision of the genus Cucullella McCoy, 1851 (Bivalvia: Nuculoida) 52Matsukuma, Akihiko: Species of Exotica (Bivalvia: Tellinidae) from New Caledonia 56Rogalla, Nicole S.; Schniebs, Katrin: The rediscovered bivalve type material of H. E. Anton 64Rueda, Jose L.; Urra, Javier; Salas, Carmen; Gofas, Serge: Bivalves associated with Zostera marina beds in southern Spain 66

Biodiversity, Palaeobiodiversity and Extinctions

Talks

De Renzi, Miquel; Ros, Sonia: Expansion of the generic diversity of bivalves during the Triassic (II): diversification of the epifaunal and infaunal stocks 24

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Harnik, Paul Gwion; Simpson, Carl: Abundance as a factor in marine bivalve extinctions over geologic time

p. 40Mandiç, Oleg; Harzhauser, Mathias: Neogene dreissenids in central Europe - evolutionary shifts and diversity changes 55Sánchez, Teresa M.: Early Ordovician bivalve radiation in the Northwestern and Famatina basins of Argentina 68

Posters

Bieler, Rüdiger; Mikkelsen, Paula: Molluscan diversity of the Florida Keys: a faunal project based on original collections, museum holdings and literature data 18Hartman, Joseph H.; Bogan, Arthur E.; Bingle, Marron: Unioniformes: repeated radiation, convergence, and paleobiogeographic considerations 41Hautmann, Michael: Key events in the Early Mesozoic evolution of bivalves 42Koppka, Jens; Hinz-Schallreuter, Ingelore: Fürsich, Franz Theodor: High-diversity bivalve faunas in the Middle Jurassic of the southern Baltic Sea 46Ros, Sonia; De Renzi, Miquel: Expansion of the generic diversity of bivalves during the Triassic (I): some comments on biases of their record 65Schneider, Simon; Hochleitner, Rupert: Great diversity in small space - a remarkable bivalve association from the Lower Pliocene of Harokopio (SW Peloponnesus, Greece) 69Wlodarska, Maria: Molluscs in Arctic Glacial fjords - Patterns of distribution and diversity shaped by glacial sedimentation 76

Freshwater Ecology and Conservation

Keynote

Richard Neves: Restoration of endangered freshwater bivalves in the United States 58

Talks

Altaba, Cristian R.: Biodiversity at crossroads: evolutionary radiation, mass extinction and global expansion among Iberian freshwater bivalves 14Araujo, R.; Toledo, C.; Machordom, A.: The Ebro river native bivalves - a problematic conservation affair 16Dunca, Elena; Mutvei, Harry; Mörth, Magnus; Winfield, Ian; Whitehouse, Martin: Environmental monitoring using shells of the freshwater pearl mussel, Margaritifera margaritifera from Lake District, UK and South Sweden 27Dunca, Elena; Söderberg, Håkan; Norrgrann, Oskar; Mutvei, Harry; Schöne, R. Bernd: Shell growth in juvenile Margaritifera margaritifera from northern Sweden 28Gatenby, Catherine M.; Patterson, Matthew A.; Devers, Julie B.; Kreeger, Danielle A.: Condition of freshwater mussels held in refugia at the White Sulphur Springs National Fish Hatchery (WSSNFH), West Virginia: is there a future for long-term mussel refugia? 35Reis, Joaquim: Patterns of distribution and population structure of Margaritifera margaritifera (L.) (Unionoidea: Margaritiferidae) in the Tua watershed (NE Portugal) 63Sousa, Ronaldo; Antunes, Carlos; Guilhermino, Lúcia: Different invasive behaviour of the non-indigenous species Corbicula fluminea (Müller, 1774) in two adjacent Portuguese estuarine ecosystems 72

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Posters

Altaba, Cristian R.; Rosell, C.; Giráldez, S.; Fernández Carretero, M. A.; Bassols, E.: Conservation plan for Unio aleroni, a critically endangered endemic naiad of the eastern Pyrenees p. 15Bataller, J. V.; Hernández, Jesús; Pradillo, Antonio: Ecology and distribution of freshwater mussels (Bivalvia: Unionidae) in the Valencia region 17Bataller, J. V.; Hernández, Jesús; Pradillo, Antonio: Presence of the alien bivalve Dreissena polymorpha (Pallas, 1771) in the Valencia region (eastern Spain) 17Delvene, G.; Araujo, R.; Bermúdez-Rochas, D. D.: Cretaceous Spanish margaritiferids 24Fernández, Carlos; Outeiro, Adolfo; Ondina, Paz; Amaro, Rafaela; San Miguel, Eduardo: The freshwater mussel Margaritifera margaritifera (L.) in Galicia, NW Spain - Preliminary study in Eo and Masma rivers 32Ghilardi, Renato Pirani; D´Agosta, Fernando César Paiva; Tavares, Sandra Aparecida Simionato; Campos, Antonio Celso de Arruda: Taphonomy of Late Cretaceous freshwater bivalves from Bauru Group, Bauru Basin (Monte Alto county, São Paulo state, Brazil): paleoenvironmental implications 36López, Miquel Àngel; Altaba, Cristian; Rouault, Thierry; Gisbert, Enric: A keystone link between two critically endangered species in European rivers: the giant freshwater pearl mussel (Margaritifera auricularia Spengler) and the European sea sturgeon (Acipenser sturio Linnaeus) 52Nakamura-Antonacci, Keiko; Guerrero Campo, Joaquín; Zapater Galve, Manuel; Catalá Roca, Carlos: Habitat selection of Margaritifera auricularia and other naiads in the Canal Imperial de Aragón, Spain 57Reis, Joaquim: Atlas of the freshwater bivalves of continental Portugal 62Sousa, Ronaldo; Freire, Ruth; Méndez, Josefina; Rufino, Marta; Gaspar, Miguel; Antunes, Carlos; Guilhermino, Lúcia: The Asian clam Corbicula fluminea (Müller, 1774) in the Minho and Lima estuaries: genetics vs. morphometry 71Zajac, Katarzyna; Zajac, Tadeusz: Habitat selection of Unio crassus 78

Marine Ecology and Palaeoecology

Talks

Borges, Luísa Maria; Cragg, Simon; Eaton, Rod: Wood boring distribution and severity of attack in European coastal waters 19Edelman-Furstenberg, Yael: Environmental reconstruction of high productivity marine settings: bivalve paleoecology of the Upper Campanian Mishash Formation, Israel 28Gibert, Jordi M.; Domènech, Rosa: Nuculoidean trace fossils in the shallow marine Miocene of the Vallès- Penedès Basin (NE Iberian peninsula) 36Gofas, Serge; Salas, Carmen: Montacutidae on the North Atlantic seamounts 37Kossak, Ute; Wahl, Martin: Interactive effects of temperature, salinity and food availability on the shell formation of Mytilus edulis 46La Perna, Rafael: Diversity of the Plio-Pleistocene Mediterranean Bivalvia: status of knowledge and prospects 48Navarro, Jorge M.; Urrutia, Geysi X.; Clasing, E.: Biodepositional rate of the mussel Mytilus chilensis and its effects on the biodiversity of benthic communities 57

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Posters

Altaba, Cristian R.; Forés, M.; Montserrat, S.: Long-term environmental record in Glycymeris inflata, a relic of old-growth soft bottoms in the Mediterranean p. 15García-March, José Rafael; Kersting, Diego Kurt: Preliminary data on the distribution and density of Pinna nobilis and Pinna rudis in the Columbretes Islands Marine Reserve (western Mediterranean, Spain) 33García-March, José Rafael; Sanchis-Solsona, Miguel Ángel; García-Carrascosa, A. Manuel: In-situ shell gaping behaviour of Pinna nobilis L., 1758 34González-Delgado, José Angel; Armenteros, Ildefonso; Civis, Jorge; Rico-García, Alberto: Stable isotopes (C, O) of the pectinid Palliolum excisum from the Lower Pliocene of the Asilah basin (NW Morocco) 38Gosselin, Marc J.; Fernández, Ernesto; Guzman, Nury; Lazareth, Claire E.; Ortlieb, Luc: Preliminary study of growth increments of the Peruvian mollusc shell Trachycardium procerum (Sowerby, 1833) (Bivalvia) throughout the last half-million years 39Higuera-Ruiz, Rubén; Elorza, Javier: Biometrical and high resolution trace element (Mg, Sr and Na) studies in Crassostrea gigas shells of three estuaries of Cantabria (Spain): seasonal, anthropogenic and ontogenetic influences 43Kersting, Diego Kurt; García-March, José Rafael; Templado, José: Evaluation of Spondylus gaederopus Linné, 1758, mass mortality event in the Columbretes Islands Marine Reserve (western Mediterranean, Spain) 45López, Gregori; Gómez-Alday, J. J.; Jiménez-Berrocoso, A.; Elorza, Javier: Inoceramid's (Bivalvia) geochemical signal: a diagenetic and palaeoenvironmental tool 51Printrakoon, Cheewarat; Tëmkin, Ilya: Comparative ecological study of two parapatric species of the genus Isognomon (Bivalvia: Pterioidea) from the southern part of Khung Krabean bay, Chantaburi province, Thailand 61Rico-García, Alberto; González-Delgado, Jóse Ángel; Civis, Jorge; Aguirre, Julio; Alonso-Gavilán, Gaspar: Pliocene pectinids of the Cadiz province (SW Spain) 63

Marine Aquaculture

Talks

Cáceres-Martínez, Jorge; Vásquez-Yeomans, Rebeca; García-Ortega, Adrián Mauricio; Balseiro, Pablo; Figueras, Antonio: Sporulated protozoan X (PEX) infecting the Japanese oyster Crasssostrea gigas in México 19Dridi, Salwa; Romdhane, Mohammed Salah; El Cafsi, M.: Analysis of the relationship between growth and sexual maturation in the bivalve Crassostrea gigas from the Bizert lagoon, Tunisia 27Galimany, Eva; Pipe, Richard K.; Jutson, Maria; Ramón, Montserrat: The effects of a toxic strain of Karlodinium veneficum on the blue mussel Mytilus edulis 33

Posters

Díaz-Díaz, Oscar; Rozbaczylo, Nicolas; Moreno, Rodrigo: Mussel beds of Perumytilus purpuratus (Lamarck, 1819) (Bivalvia: Mytilidae) on the central coast of Chile: a complex of microhabitats for polychaetes 25Dridi, Salwa; Romdhane, Mohammed Salah; El Cafsi, M.: Seasonal variation in weight and biochemical composition of the tissues of Crassostrea gigas in relation to the gametogenic

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cycle p. 26Guerra-Muñoz, Rosa Luisa; Esponda Fernández, Pedro Hernán: Transgenic embryos and larvae in mussels originated by transfection of spermatozoa 40Herrmann, Marko; Laudien, Jürgen; Arntz, Wolf; Penchaszadeh, Pablo E.: Applicability of three fluorescent markers for growth estimations of the surf clam Donax hanleyanus 43Liñero-Arana, Ildefonso; Delgado-Blas, Victor Hugo; Díaz-Díaz, Oscar; Magan, Isabel: Incidence of Polydora sp. on the mangrove oyster Crassostrea rhizhophorae (Guilding, 1828) from two coastal lagoons of Margarita Island, Venezuela 49Peña, Juan; Saavedra, Carlos; Cordero, David: Improving king scallop (Pecten jacobaeus) spat collection by the bag collector 60Ramón, Montserrat; Maynou, Francesc; Beata, Marc: Spatial variability of a Callista chione population in the western Mediterranean 62Vanegas-Espinosa, Valentina; Díaz-Díaz, Oscar; Liñero-Arana, Ildefonso: Arca zebra (Swainson, 1833) (Bivalvia: Arcoida): an ecological island for polychaete communities 74Vásquez-Yeomans, Rebeca; Cáceres-Martínez, Jorge; García-Ortega, Adrián Mauricio: Isolation and identification of bacteria associated to mortality events in Crassostrea gigas in Mexico 75Vásquez-Yeomans, Rebeca; Cáceres-Martínez, Jorge; García-Ortega, Adrián Mauricio: Oyster herpesvirus in Crassostrea gigas cultured in Mexico 75

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IMMANITAS IS AN ALBIAN-CENOMANIAN ANTILLOCAPRINID RUDIST (BIVALVIA:

HIPPURITOIDEA)

Aguilar, J.

Departament de Geologia-Area Paleontologia, Universitat Autònoma de Barcelona, Edifici Cs, 08193

Bellaterra, Barcelona, España; xava1969@yahoo.com.mx

Immanitas is a rudist genus created on material from Paso del Rio, Colima, Mexico (1); the age of sediments in this locality is Cenomanian. Until now Immanitas was considered as Uncertain Family (2), principally due to misidentification of its myocardinal structures (1), which let it out of any possible suprageneric adscription.

A recent study carried out by the author on material from El Cañon de la Servilleta in northeastern Mexico shows Immanitas besides other rudists genera as Toucasia, Douvillelia, Caprinuloidea, Mexicaprina, Planocaprina and Texicaprina. The abundance of Immanitas in this place allowed a better knowledge of its morphology and also of its variability, justifying the synonymy of its species. Immanitas presents a recumbent equivalve to inequivalve giant shell, without evidence of a ligament ridge or cavity. The anterior side shows a characteristic flange between two grooves. In the antero-ventral side there is a big cavity with tubes formed by invaginations of the outer shell wall, those tubes change in form and number from one specimen to another. The inner shell wall and all the structures in it are totally perforated by capillary canals. Its myocardinal organization, like most rudists, is formed by two teeth and two myophores around the dorsal side of the body cavity in the right valve and a left valve with one single tooth and the correspondent cavities of insertion for the myocardinal structures of the right valve. The structure of the inner shell wall, the myocardinal structures and the presence of tubes formed by the outer shell in Immanitas are characteristics of the Family Antillocaprinidae.

The family Antillocaprinidae (restricted to America), is a clade of specialized recumbent rudists considered to first appear during Campanian-Maastrichtian; however, this study points to a first appearance of the family in the Albian-Cenomanian.

(1) Palmer R 1928, California Academy of Sciences 14: 1-137.

(2) Dechaseaux C and Coogan H 1969. pp. 816-817. In: Moore R (ed.) Treatise on Invertebrate Paleontology, Part N. Mollusca 6. volume 2. Bivalvia, Geological Society of America and

University of Kansas, Lawrence, Kansas, N491-N952.

BIODIVERSITY AT CROSSROADS: EVOLUTIONARY RADIATION, MASS

EXTINCTION AND GLOBAL EXPANSION AMONG IBERIAN FRESHWATER BIVALVES

Altaba, C.R.

Laboratory of Human Systematics, University of the Balearic Islands, 07071 Palma de Mallorca, Illes

Balears (Spain); cristianr.altaba@uib.es

The combination of comparative anatomy, molecular genetics and ecology yields a novel perspective on the freshwater bivalves of the Iberian peninsula. Their diversity becomes untangled just when it is being substituted by a few globally dispersed species.

Margaritifera margaritifera is restricted to the ancient drainage systems in northwestern Iberia, where drainage-specific growth indicates differentiation within its glacial refugium. These populations thus represent a major gene pool and are among the best preserved, but are threatened by hydroelectric developments and climate change. The same challenges affect sphaeriids restricted to Alpine enclaves in high-mountain lakes of the Pyrenees, Cantabrian range and Serra da Estrela, and snowmelt seeps in Sierra Nevada.

The Atlantic watershed is inhabited by Unio delphinus and U. gibbus, vicariants of U. pictorum and U. crassus respectively, and exhibiting differentiation among drainages. On the Mediterranean side, the complex U.mancus/elongatulus is represented by several allopatric taxa, most of which deserve species status recognition. The genus Psilunio (often called Potomida, a synonym of Margaritifera) exhibits a parallel pattern, stemming from resource-tracking (parasitic larvae evolving in response to changes) of cyprinid hosts through the Neogene. Anodonta also involves hitherto unrecognized endemism; the European A. cygnea lives only in limited northern areas. Translocation of fish hosts and interconnection of drainages has resulted in unprecedented dispersal and possible mixing of previously isolated taxa. This is the case of Anodonta in lake Banyoles, a Pliocene-Quaternary lake near Girona (Catalonia) inhabited by an unusual bivalve fauna. The Ebro, largest of Iberian drainages, still harbors a remarkably rich sphaeriid and unionid fauna, resulting from its isolation and complexity. Intensive study of the extant and possibly largest viable population of Margaritifera auricularia in the lower Ebro shows that

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its life history is adapted to the dynamics of wild big rivers. Experimental evidence now supports the prediction that the European sea sturgeon was its main host, showing a keystone interaction. Even after successful captive breeding and artificial propagation, survival of M. auricularia depends critically on the river condition, now under pressure by pollution and public works as shown by the environmental long-term record encoded in shells of this species. Recently, this river has experienced massive invasion by Dreissena polymorpha and Corbicula fluminea, causing cascading ecological changes.

LONG-TERM ENVIRONMENTAL RECORD IN GLYCYMERIS INFLATA, A RELIC OF

MEDITERRANEAN OLD-GROWTH SOFT BOTTOMS

Altaba, C.R., Forés, M., and Montserrat, S.

(1*) Laboratory of Human Systematics, University of the Balearic Islands, 07071 Palma de Mallorca, Illes

Balears, Spain; cristianr.altaba@uib.es (2) C. 31 de desembre 32, 07010 Palma de Mallorca,

Illes Balears, Spain (3) Physics Department, University of the Balearic

Islands, 07071 Palma de Mallorca, Illes Balears, Spain

Glycymerids are free-living arcoid bivalves typical of sedimentary bottoms, and have a rich fossil record characterized by slow evolutionary rates and long duration of species. Four species are known to live in the Mediterranean (Glycymeris bimaculata, G. insubrica, G. glycymeris and G. pilosa), and are abundantly represented in the sediments dredged from a depth of ca. 40 m off Banyalbufar, in the northwestern coast of Mallorca. Numerous fresh and old specimens ranging from 18 to 119 mm belonging to a fifth species were found sympatrically. They are distinguished by 1) solid, strongly inflated, clearly inequilateral valves with a rounded trapezoid outline whose upper margin is smoothly arched and ends at both sides in blunt obtuse angles; 2) umbos prominent and markedly opisthogirous, covered by dense concentric ridges unaffected by an almost obsolete radial sculpture; 3) ligament area wide with long, continuous inverted V-shaped ridges, which are rather irregular and do not form a neat chevron pattern, and become much reduced giving rise to vertical riblet in very large specimens; and 4) outer color brown or greyish, inner white with a deep brown posterior blotch variable in size but always reaching the shell edge. This species has been identified as Glycymeris inflata (Brocchi, 1814), recorded since

the lower Burdigalian and throughout the Pliocene and Quaternary until the previous interglacial, in the Mediterranean, Aquitanian and Vienna basins. G. inflata is certainly absent from many comparable sites in Balearic waters. Its current limited range suggests that it survives only where slope and sediment type prevent commercial fishing. The shells exhibit clearly visible growth rings, which are presumably annual as in other marine temperate infaunal bivalves living in deep, well-mixed waters. The age of the largest individuals has been thus estimated to be around 140 years. This makes them the oldest living animals in the Mediterranean Sea, and one of the few animal species known to live beyond a century. Such extreme longevity allows examination of long time-series records of marine environmental conditions. Growth residuals exhibit variations with a periodicity of 11 years, probably related to phytoplankton production oscillations due to the solar constant.

CONSERVATION OF UNIO ALERONI, A CRITICALLY ENDANGERED ENDEMIC NAIAD OF THE EASTERN PYRENEES

Altaba, C.R., Rosell, C., Giráldez, S., Fernández, M., Carretero, M.A., and Bassols, E.

(1*) Laboratory of Human Systematics, University of the Balearic Islands, 07071 Palma de Mallorca, Illes

Balears, Spain; cristianr.altaba@uib.es (2, 3, 4) Minuartia, Estudis Ambientals, Pge. Domènech

3, 08470 Sant Celoni, Catalonia, Spain (5) Centro de Investigação em Biodiversidade e

Recursos Genéticos (CIBIO/UP), Campus Agrário de Vairão, 4485-661 Vairão, Portugal; (6) Zona Volcànica

de la Garrotxa Natural Park, Casal dels Volcans, Av. Santa Coloma s/n, 17800 Olot, Catalonia, Spain

In 1992 a surviving population of Unio aleroni, an endemic to the foothills and lowlands of the eastern Pyrenees belonging to the U. elongatulus group, was discovered near the Zona Volcànica de la Garrotxa Natural Park, in northeastern Catalonia. Since 1993, a conservation plan has been implemented, involving protection of the riverbanks, demographic and reproductive monitoring, and artificial propagation. Large-scale capture and infestation of wild fish has been performed almost every year, following the early assessment of native cyprinids as the main hosts. However, the size and age structure of adult naiads have steadily changed due to declining recruitment. This appears to be caused by a complex response to human impacts. The river bottom has become unsuitable for

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juveniles through silting with livestock sewage since 1994. Fertility has also dropped strongly, tracking variations in suspended matter concentration. In addition, individual growth has increased, suggesting a metabolic switch from reproductive effort. Moreover, the invasive American vison and the reintroduced otter appear to prey on this bivalve. Without effective protection, this population may become extinct in 15 years or less. Translocation of adults to unoccupied areas upstream and in an adjacent river had limited success, due to unusual floods and resulting disturbance of recipient sites. Recently, several small populations have been discovered in limited areas in four drainages. These relict populations are highly vulnerable, being restricted to very short stream or canal tracts. They also exhibit reduced recruitment, either because of pollution or virtual absence of fish hosts. Conservation of this species requires implementation of clean water directives, strict protection of fluvial environments currently occupied, maintenance of flow, development of captive breeding through the juvenile stage, detailed mapping of surviving populations, and establishment of new populations in safe sites. The observation of morphological and ecological differences among naiads inhabiting different drainages suggests the need for separate, urgent action plans.

SIMPLE AND CHEMICAL DNA EXTRACTION FROM PRESERVED BIVALVE

MANTLE FOR REPRODUCIBLE PCR AMPLIFICATION

Aranishi, F. and Okimoto, T.

(1, 2*) Department of Biological and Environmental Sciences, Miyazaki University, Miyazaki 889-2192,

Japan;(1) aranishi@cc.miyazaki-u.ac.jp

DNA-based studies have been one of the major interests in phylogenetic structure analysis for both wild populations and cultured broodstocks of commercially important marine bivalves. This study developed a simple and reliable method for extracting genomic DNA from preserved mantle tissues of the Pacific oyster Crassostrea gigas for reproducible PCR amplification. The methodology is based on destruction of the tissue using Proteinase K, Chelex 100 resin, detergents and urea, followed by preferentially capturing genomic DNA using silica particles. Approximately 5 mg of the tissue provided the quality and quantity of DNA enough for several hundreds of PCR reactions amplifying the hypervariable mitochondrial DNA intergenic spacer, which is a useful genetic marker for population structure

analysis of the Pacific oyster. Since being applicable for DNA preparation not only from fresh and frozen but also ethanol-preserved mantle tissues, this rapid and economical method can serve for investigating a large number of field bivalve specimens transported in ethanol at the ambient temperature from local collection sites.

THE EBRO RIVER NATIVE BIVALVES - A PROBLEMATIC CONSERVATION AFFAIR

Araujo, R., Toledo, C., and Machordom, A.

Museo Nacional de Ciencias Naturales. C/ José Gutiérrez Abascal 2 28006 Madrid, Spain;

(1*)rafael@mncn.csic.es; (2) carlostc@wanadoo.es; (3) annie@mncn.csic.es

With a length of 910 km the Ebro is not the longest Spanish stream, but together with its tributaries it occupies the largest basin of 86,098 km2 of the country and its delta is the 3rd largest in the Mediterranean. Several Sphaeriidae species - Sphaerium corneum, Musculium lacustre, Pisidium casertanum, P. personatum, P. subtruncatum, P. henslowanum - and four species of freshwater mussels (naiads) presently inhabit this basin which, with other names, were already cited by Fritz Haas: Margaritifera auricularia, Unio mancus, Potomida littoralis and Anodonta sp.

Our molecular analyses have shown that all naiad populations living in the Ebro river and its tributaries belong to these four species. The most relevant of them is the endangered Margaritifera auricularia, a species practically extinct in other parts of Europe. In Spain, the species was still present in many localities until only a few decades ago whereas its present-day distribution is largely restricted to the Canal Imperial in Aragón, an old channel which derives its water from the Ebro, with a population of near 4,000 specimens, and some scarce populations further downstream. In contrast, Potomida littoralis is still found in all basins of the Iberian peninsula and Unio mancus still inhabits numerous other Spanish Mediterranean rivers. Taxonomic studies on the Anodonta populations of the Ebro river are not yet conclusive; however, present data suggest that they do not belong to A. cygnea as is commonly asssumed.

Two invasive bivalve species have recently enriched the molluscan diversity of the Ebro basin: Corbicula fluminea, the Asiatic clam, has spread over many localities of the Ebro river, and Dreissena polymorpha, the zebra mussel, has been found in the reservoirs further downstream. However, its upstream dispersal

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within the Ebro river system is nowadays a reality. The effective conservation of the native bivalves - especially of the naiads - of the Ebro river is not only jeopardized by the massive presence of alien mollusc and fish but also by the untenable human development of the area. Water regulation and detraction in conjunction with the destruction of the last habitats of this ecosystem draw a distressing scene where the first victim will be Margaritifera auricularia.

IS THERE A CASE FOR THE SUBFAMILY AXINOPSIDINAE? : REVISING THE

TAXONOMY OF THE MINUTE THYASIRIDS OF THE GENERA ADONTORHINA,

MENDICULA, LEPTAXINUS AND AXINULUS

Barry, P.J. and McCormack, G.

(1*, 2) Martin Ryan Institute, Zoology Department, National University of Ireland, Galway, Ireland; (1*)

peter.barry@nuigalway.ie

The bivalve family Thyasiridae has representatives found in all parts of the world and in all ocean depths. This project focuses on genera of the Thyasiridae which are characterised by their small size and single demibranch in the gill, and other important morphological adaptations to the shell. The classification of this family is contentious at present with some authors splitting the family into the Thyasirinae and Axinopsidinae (1; 2) on the basis of the reduced internal morphology and modified shell form. A revision of representative genera of minute thyasirids is being undertaken to reconstruct their phylogeny and investigate whether the division of the family is well supported. A preliminary phylogeny will be presented.

(1) Bernard FR Catalogue of the living Bivalvia of the eastern Pacific Ocean: Bering Strait to Cape Horn. Canada, Department of Fisheries and Oceans, Canadian Special Publication of Fisheries and Aquatic Sciences 61: viii + 102 pp.

(2) Coan EV, Scott PV and Bernard FR. 2000. Bivalve seashells of western North America. Santa Barbara Mus. Nat. Hist. Monogr., Stud. Biodiv., 2, 766 pp.

ECOLOGY AND DISTRIBUTION OF FRESHWATER MUSSELS (BIVALVIA:

UNIONIDAE) IN THE VALENCIA REGION

Bataller, J.V., Hernández, J., and Pradillo, A.

(1*, 3) Centro para el Estudio de los Ecosistemas Acuáticos (C.E.E.A.), Ap. 6050, 46080, Valencia, Spain.

(1) jbataller.ceea@ono.com, (3) a.pradillo@hotmail.com;

(2*) Servicio de Conservación de la Biodiversidad, Consellería de Territorio y Vivienda, Francisco Cubells 7, 46011 Valencia, Spain; piscifactoria_palmar@gva.es

During the year 2005, we carried out a survey on the present distribution pattern of the freshwater mussels Unio elongatulus , Potomida littoralis, and Anodonta cygnea in the Valencia region in eastern Spain. Places from which unionids had been previously cited in the literature or mentioned in unpublished records have been sampled. When presence was corroborated, population densities were estimated by means of 15 0.25m2 sampling quadrates or by collecting all individuals within 25m2, depending on water depth, water current and transparency; we also took biometric data from the captured individuals.

Considering the total number of sampling sites with one or more mussel species, Potomida littoralis was present in 44% of all sites, Unio elongatulus in 80% and Anodonta cygnea in 48%. Sixty percent of all sampling stations contained more than one unionid species, that is, 40% were monospecific. Concerning the possible species associations, 12% of the sample sites contained all three species, in 32% we found U. elongatulus and A. cygnea, and in 16% U. elongatulus and P. littoralis. Remarkable is the absence of the association A. cygnea and P. littoralis reasons for which are not yet well understood. Anodonta cygnea typically inhabits canals and irrigation ditches; Potomida littoralis, although sometimes present in irrigation ditches, is mainly found in the middle reach of rivers. Unio elongatulus is, without doubt, the most ubiquitous species in the Valencia region which appears to have its optimum in clean and shallow water bodies with slow current.

PRESENCE OF THE ALIEN BIVALVE DREISSENA POLYMORPHA (PALLAS, 1771)

IN THE VALENCIA REGION (EASTERN SPAIN)

Bataller, J.V., Hernández, J., and Pradillo, A.

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(1*, 3)Centro para el Estudio de los Ecosistemas Acuáticos (C.E.E.A.), Ap. 6050, 46080, Valencia, Spain;

(1)jbataller.ceea@ono.com, (3) a.pradillo@hotmail.com.

(2) Servicio de Conservación de la Biodiversidad, Consellería de Territorio y Vivienda, Francisco Cubells 7, 46011 Valencia, Spain; piscifactoria_palmar@gva.es

The zebra mussel Dreissena polymorpha is an invasive species considered as a pest in North American and many European countries where numerous papers have been written on its biology, ecologic impact and control (1, 2). On the Iberian Peninsula, the species was detected in the lower Ebro river in 2001 (3). Since then, the species expansion has been recorded along the river but not beyond its basin (4). At the end of 2005, D. polymorpha was detected in the Sitchar reservoir (Castellón) following a drop in the water level.

A preliminary quantitative sampling (0.25m2 quadrate) along the reservoir perimeter reveals that the species has colonized most of the hard substrates, with a maximum density of 1810 ind/m2 at some points. The size of the larger individuals (> 27 mm) suggests that colonization began about two years ago (5). Inspections upstream and downstream the reservoir show that the invasion has not yet reached the reservoir's limits. In a coordinated effort, the environmental agency (Consellería de Territorio y Vivienda) and the river authority (Confederación Hidrográfica del Júcar) have established management measures to prevent or at least slow down further propagation of the species. These measures include a fishing and navigation ban at the Sitchar reservoir, prohibition of filling up the water tanks of fire planes in the area, erection of information panels in recreational areas near the reservoir and distribution of leaflets to visitors

(1) Schloesser DW et al. 1994, Journal of Shellfish Research, 13(1): 243-267.

(2) http://www.sgnis.org/update/zebra.htm (3) Altaba CR, Jiménez PJ and López MA 2001,

Quercus, 188: 50-51. (4) Jimenez, PJ (coord.) Localización y evaluación de

una nueva invasión biológica: el mejillón cebra (Dreissena polymorpha) en el Ebro. Mº Medio Ambiente. Madrid.

(5) Kennedy, RH and Açkakaya HR 1999, "Development of an age-structured metapopulation model of zebra mussels," Zebra Mussel Technical Notes Collection (ZMR-3-21), U.S. Army Engineer Research and Development Center, Vicksburg, MS.

MOLLUSCAN DIVERSITY OF THE FLORIDA KEYS: A FAUNAL PROJECT BASED ON

ORIGINAL COLLECTIONS, MUSEUM HOLDINGS AND LITERATURE DATA

Bieler, R. and Mikkelsen, P.M.

(1*, 2) Department of Zoology, Field Museum of Natural History, 1400, S Lake Shore Drive, Chicago, IL

60605-2496 USA

Before molluscan biodiversity of a particular region can be compared to others, before changes can be monitored, and before steps can be designed to preserve particular species, it is necessary to assess the existing (and, if possible, past) fauna. Because of the often small size and cryptic nature of the animals involved, and the specialized knowledge necessary to recognize them, there are few geographic regions for which sufficient baseline data have been assembled. A combination of new field collecting with the comparative study of historic museum collections and the analysis of existing literature can not only create such baseline data, but also reconstruct historic diversity data. Such an effort is underway for the molluscan fauna of the Florida Keys, an island chain and associated habitats at the southern tip of peninsular Florida that includes the second largest U.S. marine sanctuary with nearly 10,000 km2. This project's combination of region-wide qualitative sampling, thorough and rapid collecting techniques, "data mining" of museum collections and literature resources, as well as a large-scale transect project along the island chain, have to date nearly tripled the number of marine mollusk species known to live in the Florida Keys, to about 1,700, and given insight into their distribution and ecology in the region. Dated museum records are used to investigate occurrence/distributional patterns over the past 100+ years and are indicative of recent introductions and losses in this region. A first project phase focusing on bivalve diversity was recently completed, resulting in faunal analyses (1) and critical catalogues (2) as well as descriptions and extensive photographic documentation of nearly 400 species. The considerable clade richness (with half of the world's bivalve families represented in the regional fauna) also allowed conducting an exemplar-based comparative survey of bivalve morphology and anatomy, the focus of a forthcoming book-length treatment. [Supported, in part, by NSF PEET DEB-9978119.]

(1) Bieler R, Mikkelsen PM, 2004. Malacologia, 46: 503-544.

(2) Mikkelsen PM, Bieler R, 2004. Malacologia, 46: 545-623

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WOOD BORING DISTRIBUTION AND SEVERITY OF ATTACK IN EUROPEAN

COASTAL WATERS

Borges, L.M., Cragg, S., and Eaton, R.

Institute of Marine Sciences, School of Biological Sciences, University of Portsmouth, Ferry road,

Eastney, PO4 9LY, Portsmouth, England

The distribution of wood boring bivalves was investigated in collaboration with 18 marine institutes in Europe ranging from Turkey to Iceland. Pinus sylvestris panels were used as baits at depths of 2 to 3 metres. Bivalves that recruited to the panels were identified to the species level with the help authoritative keys. The severity of attack was evaluated based on X-rays of the panels and visual assessment under a stereo microscope, according to the categories described in EN 275 (1).

Six species of wood boring bivalve from the family Terdinidae, were found in the test sites. In Iceland no wood boring bivalves were found, the only attack observed was due to Limnoria lignorum (Isopoda: Crustacea). In Norway two bivalve species were present, Nototeredo norvagica and Psiloteredo megotara. P. megotara appears to be confined to colder North Atlantic waters as no specimens were found in southern sites. The most widely distributed species in northern Europe was Teredo navalis occurring as the only boring bivalve in Kristineberg (Sweden), Kiel (Germany), Haren and Yerseke (Netherlands). In Portsmouth (England), Teredo navalis, was also present but the dominant species was Lyrodus pedicellatus. This was the most northern site were this last species was present. In southern Europe, Lyrodus pedicellatus was clearly the dominant species in all the sites except in Bartin, Black Sea, where the sole bivalve species was Teredo navalis. The two sites with highest diversity of species was Rovinj, Croatia (4 species) and Erdemli, Turkey (5 species). In both sites Lyrodus pedicellatus was dominant but several specimens of Teredo navalis were also found. Teredo bartschi, Bankia carinata and Nototeredo norvegica were the other species present in the Mediterranean Sea. No signs of boring activity were found in the Gulf of Riga, probably due to the very low salinity of its waters (0.2 to 3.75 PSU). Complete failure of the wood panels occurred in Sweden, Yerseke (Netherlands), England, Croatia, Portugal and Turkey.

(1) EN 275 1992. Test Method for determining the protective effectiveness of a preservative against marine borers. European Committee for Standardization. pp21.

SPORULATED PROTOZOAN X (PEX) INFECTING THE JAPANESE OYSTER CRASSSOSTREA GIGAS IN MÉXICO

Cáceres-Martínez, J., Vásquez-Yeomans, R., García-Ortega, A.M., Balseiro, P., and Figueras, A.

Inexplicable mortality episodes of cultured Pacific oyster Crassostrea gigas are recurrent since 1997 in the coastal lagoons and Bays from Northwest México. During a sanitary survey of juveniles and adults of C. gigas in early 2005 we detect a kind of spores of a protozoan infecting digestive ducts and tubes. Moreover, liberation of microcells in epithelium of esophagus, digestive diverticulli, stomach and intestine was observed. Abundant diapedesis in epithelia of intestine, stomach, gills and mantle were observed. Pathological alterations such as hyperplasia, and haemocyte infiltration were associated to the presence of this parasite. At histological level this parasite showed some similitude to Marteilia sp. We propose to name this parasite as Protozoan Sporulating X (PSX) as long as its identity is not established.

IMPLICATION OF MOLECULAR DATA FOR UNIONOID GENERIC NOMENCLATURE

Campbell, D.C.

425 Scientific Collections, Box 870345, University of Alabama, Tuscaloosa AL 35487-0345 USA;

amblema@bama.ua.edu

Several recent molecular analyses indicate that many currently recognized unionoid genera are polyphyletic or paraphyletic. Traditional morphological classifications have strongly emphasized a few characters and utilized evolutionary grades rather than synapomorphies and are thus very vulnerable to homoplasy or plesiomorphy. In addition, the influential classifications of Simpson and Ortmann from the early 1900's were largely based on North American taxa, so species from other regions have often been placed into what are probably North American endemic higher taxa. Revision of the classification of the Unionoida requires both extensive phylogenetic reinvestigation and review of the literature to identify available genus names. A combination of inadequate descriptions and lack of type designations in early references, especially the work of Rafinesque and Swainson, makes identification of the actual type species difficult. The present research combines new and published molecular data with review of early literature to determine what clades

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appear well-supported and whether names are available for them.

Several names in current use require revision. For example, Cyclonaias is an objective synonym of Rotundaria, which becomes the oldest available name for a major subgroup of Quadrula. Anadontina, usually buried in synonymy of the eastern North American Alasmidonta, is an overlooked senior synonym of Lamellidens, a major south Asian genus. Potomida is the oldest available genus for Margaritifera auricularia, if it is separated from Margaritifera, rather than for Psilunio littoralis. Nodularia, often treated as a synonym of Unio, appears genetically well-differentiated. Although current usage includes numeous independent clades in Lampsilis and Villosa, almost no names exist for dividing up these heterogeneous groups. True Anodonta probably does not exist in eastern North America, though the western North American Anodonta species are not far from A. cygnea. Revision of the classification of this diverse, imperiled group of bivalves will provide a better guide to their true relationships and thus of their biology than the current nomenclature, but it will require extensive effort.

GENETIC VARIABILITY OF CHILEAN AND PERUVIAN SURF CLAMS (DONAX

MARINCOVICHI AND DONAX OBESULUS)

Carstensen, D., Herrmann, M., Laudien, J., Schiel, S., Arntz, W., Leese, F., and Held, C.

Alfred Wegener Institute for Polar and Marine Research Bremerhaven, Germany; (1*)

dcarstensen@awi-bremerhaven.de

Exposed intertidal sandy beaches are commonly dominated by surf clams of the genus Donax. In Peru and Chile these bivalves play an important role for artisanal fisheries. Beside that, little is known about the taxonomy, biology, and the clam's susceptibility to climatically induced changes. The taxonomic status of the two "species" Donax marincovichi and Donax obesulus, distributed along the Peruvian coastline, is controversially discussed. As morphometric comparisons reveal no significant differences we possibly deal with a single rather than with two species. Furthermore, our knowledge on larval dispersal allowing gene flow among populations is scarce. Therefore, both putative Donax species were sampled at ten beaches along the coastline from northern Chile to northern Peru. Partial cytochrome oxidase I sequences were analysed in order to estimate the genetic distances

between both putative species and to estimate the intraspecific gene flow along the coastline. Region specific patterns and the dependence on recruitment of local stocks are discussed.

MORPHOLOGICAL PHYLOGENETICS OF THE EARLY BIVALVIA

Carter, J.G., Campbell, D.C., and Campbell, M.R.

(1*) Department of Geological Sciences, University of North Carolina at Chapel Hill, NC 27599-3315, USA;

treatise@unc.edu. (2) Department of Biological Sciences, Biodiversity and

Systematics, University of Alabama, Box 870345, Tuscaloosa, AL, 35847-0345, USA;

amblema@bama.ua.edu. (3) 2233 Mount Pleasant Road, Bloomington, IN,

47421, USA; ecphora@indiana.edu.

Fossil bivalves provide ample characters of shell morphology, hinge dentition, ligament structure, shell-muscle scars, and shell and ligament microstructure to provide a sound basis for phylogenetic studies independent of genetics and soft anatomy. Such studies have an advantage over neontological approaches because they permit the researcher to focus on older, more plesiomorphic members of a clade, thereby reducing convergence, and because they can identify ancestors as opposed to just close common ancestry. The present study of 296 predominantly Paleozoic and Mesozoic bivalves is based on 126 parsimony-informative characters for the Subclass Palaeotaxodonta, 183 for the Superorder Pteriomorphia, and 156 for the Superorder Heteroconchia.

The analysis of 40 Palaeotaxodonta resulted in 14 most parsimonious trees with 613 steps. The strict consensus tree showed the Solemyidae as a sister group to Early Ordovician Afghanodesma (Nuculoidea) and the paraphyletic family Praenuculidae (Nuculoidea). The Praenuculidae gave rise independently to the Nuculidae, and then, in no indicated order, to the Tironuculidae (Nuculoidea), Malletiidae (Nuculanoidea), Ctenodontidae, and a polyphyletic Cardiolariidae. The majority rule consensus tree provided a more definitive sequence, with the Praenuculidae giving rise to the Nuculidae, then the Ctenodontidae, Tironuculidae, and Malletiidae, with the Cardiolariidae being polyphyletic. These results are compatible with neontological evidence for very close affinity between the Solemyoidea and the Nuculoidea (1), but they contradict paleontological evidence that the Ctenodontidae gave rise to the Solemyidae (2). Secondary loss of hinge teeth

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in solemyids may be responsible for this discrepancy. In order to evaluate this hypothesis, the distinctive shell shape of ctenodontids and solemyids was heavily weighted. Two very different but equally parsimonious scenarios emerged. The first scenario showed Early Ordovician Thoralia and the clade of Ctenodontidae + Solemyidae as a sister group to the paraphyletic Praenuculidae, with the latter giving rise to a clade of Malletiidae + polyphyletic Cardiolariidae, then to the Tironuculidae, and lastly to the Nuculidae. This scenario is incompatible with monophyly of the Palaeotaxodonta and with evidence for the Nuculoidea-Solemyoidea clade. The second scenario seems more plausible. Here Afghanodesma is basal to the paraphylectic Praenuculidae, which gives rise sequentially to the Malletiidae, Tironuculidae, Nuculidae, and the Ctenodontidae + Solemyidae clade, with the Cardiolariidae polyphyletic. All of these analyses identify nacre as plesiomorphic within the Palaeotaxodonta.

The analysis of 111 pteriomorphians resulted in 744 most parsimonious trees with 2231 steps. The strict consensus tree showed a basal dichotomy between the Arcoida (Glyptarcoidea and Arcoidea) + Frejidae + Umburridae + Rhombopteriidae, and the rest of the Pteriomorphia, with the latter branching as follows: [1] Cyrtodontidae + Falcatodontidae, [2] Yonginella (Cyrtodontidae), [3] Praecardioida plus Mytiloida (the latter including the Modiolodonidae, Colpomyidae, Evyanidae, Matheriidae, and Modiolopsidae, with the Modiolopsidae giving rise to Mytiloidea), [4] Ambonychioidea, with the Ambonychiidae giving rise to the Eurydesmidae (Monotoidea), [5] Myalinidae (Ambonychioidea), [6] Pterineidae (Pterioidea), giving rise to the Pinnoidea and Myodakryotidae, [7] Leiopectinidae (Pterinopectinoidea), [8] Pterinopectinidae (Pterinopectinoidea), [9] Oxytomidae (Monotoidea) + Cassianoididae (Aviculopectinoidea) + Ostreoidea, [10] Heteropecten cf. eaglensis + Limipecten (both Etheripectinidae) + Acanthopectinidae (all Aviculopectinoidea), [11] Heteropecten exemplarius, [12] Palaeolima retifera (Limoidea), [13] a clade of other Pseudomonotidae (Leptochondriidae + Hunanopectinidae) + Aviculopectinoidea (Aviculopectinidae, Deltopectinidae, Streblochondriidae), with the Pseudomonotidae giving rise to the Euchondriidae (Aviculopectinoidea) and Permanomiidae (Anomioidea), and [14] a clade of other Aviculopectinoidea (Aviculopectinidae, Deltopectinidae, Streblochondriidae) giving rise to both the Chaenocardiidae (Monotoidea) and the Pectinoidea. In these analyses nacre is identified as the ancestral microstructure in the Pteriomorphia, rather than porcelaneous structure as suggested by Cope (3). The presence of nacre without foliated structure in some early oysters (4) suggests that the Ostreoidea did not

evolve from nacreous/foliated aviciulopectinoideans, as the present analysis suggests. Weighting the presence of nacre changes the outcome of the analysis by separating the Ostreoidea from the Oxytomidae and making the Ostreoidea and Aviculopectinoidea basal sister groups in a clade derived from the Pterinopectinidae. In this weighted analysis the Oxytomidae are still closely allied with the aviculopectinoidean family Cassianoididae, Palaeolima becomes a sister taxon to certain species of Pseudomonotis, and the partially nacreous Euchondriidae are removed from the Pseudomonotoidea and placed more appropriately within their superfamily Aviculopectinoidea.

The analysis of 142 heteroconchs resulted in 18098 most parsimonious trees with 2279 steps. The strict consensus tree showed a basal dichotomy between [1] a clade with a branching sequence of Modiomorphoidea (Modiomorphidae + Hippopodiidae) followed by Pholadomyoida, Thoralia, and the Trigonioida, with the Trigonioidea giving rise to the Unionoidea through the Pachycardiidae, and [2] a clade with basal Paleozoic "lucinoids" (Babinka, Coxiconcha, Paracyclas, Ilionia) followed by the Redoniidae, a clade of Cycloconchidae + (Montanariidae + Lyrodesmatidae), then most Crassatelloidea (paraphyletic, with mecynodontid, permophorid and palaeocarditid decendants), followed by the Cardioidea and Carditoidea.

(1) Giribet G and Wheeler W 2002. Invertebrate Biology, 121(4): 271-324.

(2) Pojeta J Jr 1988. New Mexico Bureau of Mines and Mineral Resources, Memoir 44: 201-271.

(3) Cope, J. 1997. Palaeontology, 40: 713-746. (4) Carter JG 1990. p. 218 (135-296), In: JG Carter

(ed.), Skeletal biomineralization: patterns, processes and evolutionary trends. Vol. I. Van Nostrand Reinhold, New York.

BIOMINERALIZATION OF NACRE IN MOLLUSCS

Checa, A.G.

Departamento de Estratigrafia y Paleontología, Facultad de Ciencias, Universidad de Granada,

Avenida Fuentenueva s/n, 18071 Granada, Spain; acheca@ugr.es

Nacre is probably the most studied natural biocomposite in invertebrates, due to its excellent biomechanical, biomedical and aesthetic capabilities. It is fabricated by monoplacophorans, some bivalves and gastropods and the cephalopods Nautilus and Spirula. Nacre is said to have a brick-and-mortar structure, the bricks being

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aragonite platelets (whether mono- or polycrystalline) and mortar referring to the arrangement of organic membranes. Nacre platelets are arranged onto superimposed lamellae. There are two kinds of organic membranes: interlamellar, extending between lamellae, and pericrystalline, completely surrounding every plate. Organic membranes consist of three basic components: the ß-chitin core of the interlamellar membranes, glycoproteins shielding the chitin framework and silk-like fibroin forming the pericrystalline membrane and the intracrystalline matrix. All the organic and mineral components are expelled into the extrapallial space, in the form of ions, molecules, and polymers, where they have to self-assemble to produce such a complex organo-mineral structure. Previous and recent observations demonstrate that the organic interlamellar membranes are formed first. The mode in which this process is carried out is not yet completely understood, but we propose that the chitin core initially forms a cholesteric liquid crystal mesophase, which is later covered on both sides by glycoproteins. The fibroin component would then aggregate within the interlamellar space. Aragonite crystals nucleate and grow within this space and both trap and develop a permanent cover of silk-fibroin, which in this way forms the intracrystalline matrix and the pericrystalline membranes. The liquid-crystal model explains the complex labyrinthine patterns usually observed in bivalves as crystal defects and 2-D nucleation processes of the chitin core. Defects are brought to a minimum in gastropods because the whole mineralization compartment of nacre is protected by a thick surface membrane which acts as a template for the formation of the interlamellar membranes. In summary, the whole arrangement of nacre lamellae is organized by the interlamellar membranes, the mineral phase acting as decoration of the organic pattern. This does not mean that aragonite platelets grow passively. It is proposed that crystal competition processes at the growth front of nacre terraces in bivalves cause a good biaxial alignment of crystals. This is not possible in gastropod nacre, due to its towered mode of growth. The mode of nacre organization is only partially known in bivalves and gastropods, many aspects being still obscure or controversial even in these groups. Further insight is obviously needed to reach a basic body of knowledge. Unless this stage is reached there is little hope of successfully biomimetizing this fascinating biomaterial.

MICRORIDGES IN THE INNER DORSAL SHELL OF PECTINIDS

Checa, A.G., Esteban-Delgado, F.J., and Salas, C.

(1*, 2) Departamento de Estratigrafia y Paleontología, Facultad de Ciencias, Universidad de Granada,

Avenida Fuentenueva s/n, 18071 Granada, Spain; (1*) acheca@ugr.es; (2) fjesteb@ugr.es;

(3) Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos

s/n, 29071 Málaga, Spain; casanova@uma.es

Microridges are tiny ridges which appear in the dorsum of the valve interiors in Pectinidae, Propeamussiidae and Spondylidae. Given that these structures have not seemingly been described earlier and their persistence within the mentioned families, we have undertaken a SEM and TEM-based study of the morphology, distribution and microstructure of the microridges present in the family Pectinidae and of their associated mantle in order to obtain morphogenetic conclusions.

In this family microridges have widths between 15-30 µm and alternate with similarly sized depressions. They elongate dorsoventrally and are mutually parallel, although they frequently diverge, fuse and intercalate, thus forming a certain dendritic pattern. They extend from both sides of the resilifer close to the ends of both valve wings. Microstructurally they are calcitic spherulitic outgrowths developed onto the normal foliated layer. The microridges only grow in length, but not in width. Therefore, during the shell growth, their number increases by addition at the left and right ends. The microridges on one valve tightly interpenetrate the inter-ridge depressions of the opposing valve and viceversa, in a hinge-like fashion. In Pecten maximus the dorsal mantle epithelium adapts to the shape of the microridges, although it only adheres to the elevations but not to the depressions. The epidermis consists of cuboidal cells, with microvillar borders and some gland cells seated on the basal lamina overlying the internal connective tissue. At the convexities facing the depressions between ridges, there are tall epithelial cells with frequent mucous glands. At the concavities facing the ridges the epithelial cells are shorter, and have many mitochondria and well developed endoplasmic reticuli and Golgi apparatuses. These traits are indicative of metabolic activity, probably related to the calcification process. From the morphogenetic viewpoint, the microridges initiate by local folding of the mantle margin. A microanticline with dorsoventral axis thus forms, which initiates an underlying spherulitic deposit. When this ridge acquires a certain elevation the mantle loses contact with the shell at the synclines. Although

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their function is speculative, microridges seemingly act in a hinge-like fashion. Their study may provide clues to understand the development of the taxodont hinge.

THE RUDISTS FROM THE CENOMANIAN-TURONIAN BEDS OF THE GAFSA REGION

(TUNISIA)

Chikhi-Aouimeur, F., Abdallah, H., Pons, J.M., and Vicens, E.

(1) Université H. Boumediènne, Bab Ezzouar - BP 32 El Alia, Algiers 16000, Algeria; fet_aouimeur@yahoo.fr

(2) Laboratoire de Géoressources, CERTE, Technopôle de Borj Cédria, BP 95, 2050 Hammam-Lif, Tunisia;

Hassen.Abdallah@inrst.rnrt.tn (3, 4) Universitat Autònoma de Barcelona, Departament

de Geologia, Facultat de Ciències, Edifici Cs, 08193 Bellaterra, Spain

josepmaria.pons@uab.es, enric.vicens@uab.es

During Late Cenomanian and Turonian the Gafsa region presented a framework of basins and highs where rudists became well represented when local conditions were favourable. Recent studies in the area on ammonites and microfossils (1,4) have refined the biostratigraphy, and others on sedimentology the depositional history (2,3), allowing a fairly precise biostratigraphical and environmental setting of the rudist formations. Nevertheless, this fauna although frequent and well preserved has not been adequately described. Sampling carried on the northern, southern, and eastern margins of the Gafsa-Metlaoui Basin allowed us to describe its composition and distribution.

The Late Cenomanian Zebbag Formation (Jebel Zitouna, Jebel Ben Younès) yields Praeradiolites biskarensis. As this species is widespread and always found below Neolobites vibrayeanus along the southern margin of the Tethys, it is a good marker from Morocco to the Middle East.

Durania (D. arnaudi and D. blayaci) is frequent in the deeper facies of the Upper Cenomanian-basal Turonian; such as in the basin deposits of the Bahloul or of the Gattar Equivalent occurring, together with ammonites and planktonic foraminifers, below the Lower Turonian levels with Thomasites rollandi or Pseudaspidoceras flexuosum.

At Mid Turonian, deposits are less differentiated and composed of shallow platform facies (Bireno Member), biostratigraphy is based on benthic foraminifers and ostracods. At Jebel Ben Younès, Jebel Chemsi and Jebel Zitouna rudists are very abundant, particularly the

radiolitids: Biradiolites angulosus, Bournonia africana (synonym of B. lecocqi and B. fourtaui), Distefanella bassanii, Eoradiolites liratus (normally quoted only in the Cenomanian), Praeradiolites ponsianus, Radiolites trigeri, and R. praesauvagesi. Rudists are found in the highstand deposits and they disappear after the generalised emersion of the considered region.

In conclusion, the region of Gafsa results to be of great interest for the study of the Cenomanian - Turonian rudists fauna. A better calibration of its richness and distribution in south-central Tunisia would be possible by comparing this rudist fauna with that of the Kasserine region.

(1) Abdallah H, Ben Youssef M, Saïd-Benzarti R, 2003, Revue de Paléobiologie, Genève 22(1): 439-456

(2) Abdallah H, Sassi S, Meister C, Souissi F, 2000, Cretaceous Research 21: 35-106

(3) Abdallah H, Sassi S, Souissi F, Meister C, Néraudeau D, Abdeljaoued S, Saïd-Benzarti R, 2003, In: Salem MJ, Oun KM (eds.) The Geology of Northwest Libya, Sedimentary Basins of Libya-Second Symposium. Gutenberg Press, Malta 1: 99-138

(4) Meister C, Abdallah H, 2005, Revue de Paléobiologie, Genève 24(1): 111-199

PHYLOGENETIC RELATIONSHIPS OF THE ARCOIDA

Crowley, L.

American Museum of Natural History, New York, NY, USA and Graduate School and University Center, City

University of New York; crowley@amnh.org

The Arcoida is an extant order of bivalves, characterized by possession of a shell microstructure suited to form a strong, interlocking hinge and a duplivincular ligament. Relationships among the families of the Arcoida are not well understood and there have been many alternative classifications proposed for this group. While most taxonomic studies divide the order into two superfamilies: Arcoidea and Limopsoidea, others have raised the three limopsoidean families of Wilson (1998) to superfamilial status. Moreover, while recent molecular analyses of the Bivalvia support the monophyly of Arcoida, they do not support the monophyly of the superfamily, Arcoidea, which is paraphyletic with respect to Glycymeridoidea. A cladistic analysis of selected members of this bivalve order is investigated using both traditional and molecular characters. These data were analyzed using

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optimization alignment and provide insight into the evolution and diversification of the group.

(1) Wilson, B. R. 1998. In: Beesley, P. L., Ross, G. J. B. & A. Wells, (eds.), Mollusca: The Southern Synthesis. CSIRO Publishing, Melbourne, pp. 249-288.

CRETACEOUS SPANISH MARGARITIFERIDS

Delvene, G., Araujo, R., and Bermúdez-Rochas, D.D.

(1*, 3) Museo Geominero (IGME), C/. Ríos Rosas, 23, 28003 Madrid, Spain; g.delvene@igme.es;

d.bermudez@igme.es (2) Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, 28006

Madrid, Spain; rafael@mncn.csic.es

Here we describe a bivalve-fish association from the Spanish Lower Cretaceous and interpret it with respect to a putative biological (host-parasite) relation. The association is located in the northern Spanish Cameros basin, which is famous for the presence of dinosaur tracks. Samples were collected from the Valdehierro site (lithological Group Urbión of late Hauterivian-early Barremian age). The palaeo-ecosystem has been interpreted as a meandering fluvial floodplain with temporary small shallow carbonate lakes (1). The Cameros basin has a rich freshwater bivalve association dominated by Unio idubedae Palacios y Sánchez, with both juvenile and adult specimens. We compare this species with the shell of the recent European naiad Margaritifera auricularia, trying to match the few characters available and giving a new interpretation of these fossils.

Our preliminary results indicate that Unio idubedae belongs to the genus Margaritifera suggesting the presence of this genus at least since the early Cretaceous. This conclusion is in agreement with a previous study (2). However, while that study was based on "strange" specimens from a Spanish Weald basin, our interpretation is supported by the type material of Unio idubedae as well as additional specimens collected at the type locality. Although we are presently lacking direct evidence for a relation between mollusc and fish (that is, the presence of glochidia), all taphonomic features suggest that the two groups belong to the same palaeocommunity. The ichthyological remains correspond mainly to ganoid scales of fishes belonging to the order Semionotiformes (Actinopterygii, Neopterygii). Assumed that a mussel-fish symbiosis was already established in the Cretaceous, the host fish of these Spanish margaritiferids could have been a

semionotiform type. However, the extinction of this fish Order at the end of this period would have necessitated a change to other fish groups along the Cretaceous.

(1) Barrenechea JF. 1993. PhD. Universidad Complutense de Madrid, 299 pp.

(2) Mongin, D. 1966. Notas y Comunicaciones del Instituto Geológico y Minero de España, 91: 41-60

EXPANSION OF THE GENERIC DIVERSITY OF BIVALVES DURING THE TRIASSIC (II):

DIVERSIFICATION OF THE EPIFAUNAL AND INFAUNAL STOCKS

De Renzi, M. and Ros, S.

(1, 2) Institut Cavanilles, Universitat de València. Apartado Oficial 22085. Valencia E-46071, Spain

Bivalves were affected by the Permo-Triassic extinction as well as other groups. A previous paper considered how marine bivalves were diversified at the generic level during the Triassic times and which the fate of them was, irrespective of their mode of life (1). The technique used was cohort analysis (2). Now, we are going to take into account the mode of life. We made up two large groups: on the one hand, epifaunal genera and on the other hand, infaunal genera; they are not equivalent to monophyletic clades, as it is well known. Genera arising during the Triassic period come from (3); modes of life come from literature. The sample consists of 169 genera. The mode of life could be established for 157 genera. Different modes of life are assumed to influence differentially the survival of the new genera (i) during the Triassic and (ii) along all the remaining Phanerozoic times. A first approach consists of following the pattern of origination and extinction throughout the Triassic for these two groups and the later decay of them until the base of the Pleistocene. A first expansive phase is common to them, but infaunal bivalves are always underrepresented. A feature of preservation is involved here: all the infaunal bivalves have aragonitic shell and are thus poorly preserved (4). Rates of extinction seem to be larger for the epifaunal s.l. group until the end of the Carnian, but this character is not constant after this stage. Interpretation of the analysis of cohorts must take into account features such as the essay of adaptive innovations; i.e., siphons, their sloppiness, selective vulnerability or fitness of the old designs and so on.

(1) De Renzi M & Ros S 2004, XX Jornadas de la Sociedad Española de Paleontología. Libro de

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Resúmenes: 53-54, Taller de Imprenta de la Universidad de Alcalá de Henares.

(2) Raup DM 1978, Paleobiology 4: 1-15. (3) Sepkoski JJ Jr 2002, Bulletins of American

Paleontology 363: 560 pp. (4) Ros S & De Renzi M 2005, Ameghiniana 42: 549-

558.

MUSSEL BEDS OF PERUMYTILUS PURPURATUS (LAMARCK, 1819)

(BIVALVIA: MYTILIDAE) ON THE CENTRAL COAST OF CHILE: A COMPLEX OF MICROHABITATS FOR POLYCHAETES

Díaz-Díaz, O., Rozbaczylo, N., and Moreno, R.

(1*) Departamento de Biología Marina, Instituto Oceanográfico de Venezuela, Universidad de Oriente.

Venezuela; oscarfelipediazd@yahoo.com; (2, 3) Departamento de Ecologia. Facultad de Ciencias

Biologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile

Perumytilus purpuratus is widely distributed throughout the intertidal zone of the Chilean coast (1) and plays an important role in the trophic structure of the rocky shore (2). On one hand, it significantly contributes to the diet of Octopus mimus and the kelp gull Larus dominicanus, on the other hand, like other gregarious bivalve molluscs, this mussel provides a great number of microhabitats for an important variety of invertebrates including polychaetes (3). In order to identify the polychaete community associated with P. purpuratus, a seasonal field study was conducted (summer and winter) on a beach in Las Cruces, on the central coast of Chile (33º31'S, 71º38'W). Sampling was done at four stations of the intertidal zone considering zones that were exposed and protected from wave action. At each station two samples were taken, one from the level of Jehlius cirratus (Cirripedia) and one from the level of Lessonia nigrescens (Algae) for each season (summer and winter). Using a 0.04 m-2 quadrate, all the mussels and associated organisms within the quadrat were removed using a knife and spatula. The organisms were placed in previously labeled plastic bags. In the laboratory the polychaetes were filtered out with a 500µm mesh and were fixed in a solution of 10% formaldehyde. Al organisms were identified to the species level and counted.

We analyzed 2523 polychaetes belonging to 29 species and 14 families. The best represented families were Nereididae and Terebellidae, each with five species. Boccardia tricuspa was one of the most abundant

species during the summer, representing 32.6% of the total collected for this period; however, this species was absent during winter, when Pseudonereis gallapagensis represented 33.9% of the total species. Significant differences were found (ts=7.756 ***) between seasonal abundances, with greater abundance and species richness during the summer (3025 ind./m2 and 24 species). The diversity and evenness were similar for both periods.

(1) Prado L and Castilla JC 2006. J. Mar. Biol. Ass U.K. 86: 417.421.

(2) Tokeshi, M. 1995. Mar. Ecol. Prog. Ser. 125: 137-147.

(3) Liñero-Arana I. 1999. Bol. Inst. Oceanogr. Venezuela, Univ. Oriente, 38(2): 53-61.

GENETIC STRUCTURING OF MYTILUS GALLOPROVINCIALIS AT IBERIAN COASTS

Diz, A. and Presa, P.

(1, 2*) University of Vigo, Faculty of Biology, Department of Biochemistry, Genetics and Immunology,

36310 Vigo, Spain

The biogeographic region of the Gibraltar Strait has been proposed as an effective marine barrier to gene flow between populations, especially at the Almería-Orán oceanographic front (1). Studies performed with different organisms and molecular markers have shown that a long dispersal ability of larvae or adults does not imply the absence of genetic structuring. Mytilus galloprovincialis is distributed in the Atlantic and Mediterranean Iberian coasts, and several studies using mtDNA and allozymes have detected a restricted gene flow between these regions (2). The aim of this work was to study 17 populations of M. galloprovincialis from the Iberian Peninsula with six microsatellites, to assess the extent of the information gain afforded from these markers in this scenario of marine differentiation.

Similar levels of gene diversity were observed between populations and between regions, though there were more private alleles in the Atlantic region. The phylogenetic analysis placed the Mediterranean samples of the Alboran Sea intermingled with Atlantic populations. This result shows that in biogeographical terms the Atlantic region extends up to the Almería-Orán front, where the strongest barrier to gene flow was detected. The differentiation values were significant between these oceanographic regions (FST = 0.0287, P< 0.001), mainly due to two microsatellites as shown after per locus AMOVA analysis. These results obtained with microsatellites are congruent with previous genetic

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studies on Iberian mussel populations (3). However the abrupt change of some allele frequencies argues against a progressive clinal change across this barrier. This research is relevant to better understand how this marine barrier works as well as for the genetic management of Iberian populations of M. galloprovincialis. [Funded with the MEC project BIO2001-3659 and sponsored by Hucoa-Erloss]

(1) Tintore J et al. 1988, Journal of Physical Oceanography 18: 1384-1397.

(2) Quesada H et al. 1995, Marine Ecology Progress Series 116: 99-115.

(3) Sanjuan A et al. 1994, Marine Ecology Progress Series 113: 131-146

GAMETOGENIC CYCLE OF MYTILUS IN GALWAY BAY

Doherty, S.D., Brophy, D., and Gosling, E.

(1*, 3) Molecular Ecology Research Group. Galway-Mayo Institute of Technology, Dublin Rd., Galway,

Ireland; dohertysd@gmail.com (2) Commercial Fisheries Research Group. Galway-Mayo Institute of Technology, Dublin Rd., Galway,

Ireland

The coastal waters of northwest Europe are inhabited by two members of the Mytilus genus. In areas where two taxa occur sympatrically, hybridisation is known to occur, the extent of which varies depending on locality. (1) The zone of contact between Mytilus edulis and Mytilus galloprovincialis in western Europe (which spans more than 1400km of coastline) has been extensively studied. Using the diagnostic DNA marker Me15/16 sympatric populations have been identified on all Irish coasts with the exception of the Irish Sea coast (Doherty, unpublished data). The high frequency of hybrids indicates that reproductive isolating mechanisms are not sufficient to prevent hybridisation. Also there is a possibility of hybrid individuals being fertile, therefore having the ability to backcross with pure individuals.

(2) Previous investigations have found that Irish mussel populations exhibit seasonal protracted spawning, with peak activity in March/April and July/August. Due to the high degree of morphological similarity between the two taxa it is impossible to separate the types visually. As a result, reproductive studies in Ireland have treated mussel populations as panmictic populations of M. edulis alone.

As there is currently no data on the reproductive cycles of M. edulis and M. galloprovincialis in Irish waters this present study aims to investigate whether Mytilus spawn asynchronously in Irish waters, whether they exhibit differences in reproductive output and to ascertain if there is differential viability between the three taxa. A combination of molecular (PCR), histological and image analysis techniques are being employed. The results of this study should shed some light on the reproductive isolating mechanisms at play in the northwest European hybrid zone, while also providing valuable information on the reproductive cycle of a commercially important species in Irish waters.

(1) Gosling EM 1992, In: The mussel Mytilus: ecology, physiology, genetics and culture (EM Gosling, ed.). Elsevier. Developments in Aquaculture and Fisheries Science no. 25: 1-20.

(2) King PA, McGrath D, Gosling E 1989, Journal of the Marine Biological Association of the United Kingdom, 69(2): 355-365

SEASONAL VARIATION IN WEIGHT AND BIOCHEMICAL COMPOSITION OF THE

TISSUES OF CRASSOSTREA GIGAS IN RELATION TO THE GAMETOGENIC CYCLE

Dridi, S., Romdhane, M.S., and El Cafsi, M.'.

(1*, 3) Faculté des Sciences de Tunis/ Département de Biologie, Laboratoire de Physiologie de la Nutrition,

Campus Universitaire, 1060 Tunis, Tunisia ; salwadridi@yahoo.fr

(2) Institut National Agronomique de Tunisie/, Département des sciences de la Production animale et

de la pêche, 43 Av. Charles Nicole, 1082 Tunis, Tunisia.

Seasonal variations in biochemical composition of the bivalve C.gigas was studied from February 2002 until January 2003 in the Bizert lagoon in relation to environmental conditions and reproductive events. Separate analyses were made of gonad-visceral mass. The gametogenic cycle comprised tow phases: gametogenesis including ripeness and spawning (March - September) and sexual repose during the rest of the year. The cupped oyster Crassostrea gigas in the Bizert lagoon showed a clear cycle of energy storage and utilization. Total biochemical composition was about 6.50 % ( 3.01 of dry weight in glycogen, 14.34 % ( 3.60 of dry weight in protein and 6.67 % ( 1.34 of dry weight in lipids. Lipid and glycogen concentrations in the gonad - visceral mass were inversely related: maximum concentrations of glycogen occurred between December and February and corresponded with minimum

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concentrations of lipids. High glycogen contents recorded in winter supported the processes of gamatogenesis and then decreased progressively to attain low values at maturity and during summer corresponded to the first spent (June) and the began of total spawning, however lipids are accumulated in gonads during the period of maximum ripeness (spring) and then decreases in summer. During autumn, the increase of total fatty acids values appeared to be related to the available food in association with an increase in the chlorophyll a concentrations. Protein contents remained similar variations with lipids concentrations throughout the year. High protein levels occurred in May and in July which corresponded to oocyte maturation and then decreased in late summer (began of total spawning). At the expense of the available food in autumn, protein concentrations increase again to assure recovery of the tissue weight of the bivalve, which induced an increase in the condition indices values.

ANALYSIS OF THE RELATIONSHIP BETWEEN GROWTH AND SEXUAL

MATURATION IN THE BIVALVE CRASSOSTREA GIGAS FROM THE BIZERT

LAGOON, TUNISIA

Dridi, S., Romdhane, M.S., and El Cafsi, M.'.

(1, 3) Faculté des Sciences de Tunis/ Département de Biologie, Laboratoire de Physiologie de la Nutrition,

Campus Universitaire, 1060 Tunis, Tunisia ; salwadridi@yahoo.fr

(2) Institut National Agronomique de Tunisie, Département des sciences de la Production animale et

de la pêche, 43 Av. Charles Nicole, 1082 Tunis, Tunisia.

The relationship between growth and sexual maturation of the bivalve Crassostrea gigas was studied from February 2002 to January 2003. Different measurements of length and weight on each specimen are associated with the processes of reproduction and environmental parameters, especially food availability. Separation between oysters in the two phases of gametogenic cycle demonstrated a higher correlation between the different parameters of growth models during sexual repose than during gonadal activity. During the gametogenic inactivity, high condition indices (CI) are caused by autumnal phytoplankton abundance which induces organic matter accumulation and increases of tissues dry weight and shell length. On the other hand, CI levels decrease in June, July and September which corresponds to spawning. Oysters spent most of their energy reserves in the reproduction effort and little is

dedicated to the process of growth. This explains why correlations between the different parameters of growth during this phase of the reproductive cycle are low. These relationships between shell growth and sexual maturation are confirmed in some other bivalve species.

ENVIRONMENTAL MONITORING USING SHELLS OF THE FRESHWATER PEARL

MUSSEL, MARGARITIFERA MARGARITIFERA FROM LAKE DISTRICT,

UK AND SOUTH SWEDEN

Dunca, E., Mutvei, H., Mörth, M., Winfield, I., and Whitehouse, M.

(1*,2, 5) Swedish Museum of Natural History, Box 50007, S-10405 Stockholm, Sweden; (1*)

elena.dunca@nrm.se, (2) harry.mutvei @nrm.se, (5) martin.witehouse@nrm.se;

(3) Stockholm University, Dept of Geochemistry, Stockholm, Sweden; magnus.morth@geo.su.se; (4) Centre for Ecology & Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg,

Lancaster LA1 4AP, UK; ijw@ceh.ac.uk

Mussels are monitors of the environment in which they grow. They store in their shells information about element dynamics in the surrounding water and thereby, also environmental parameters as pH and temperature, are indirectly monitored (1). In the present paper we focus on annual growth rates, microgrowth structures and intra-annual elemental distributions in shells of Margaritifera margaritifera, from two different populations living in unpolluted environment: Borrans Beck, England and Vramsån River, South Sweden. Annual growth measurements and microgrowth analysis were performed on transversal shell sections. Population growth curves were established using techniques employed by dendrochronologists.

The population growth curves of M. margaritifera from the two rivers correlate with each other as well as with the population growth curve of Unio crassus from Vramsån River. All growth curves correlate with summer temperatures. In the outer prismatic layer each annual increment shows a specific pattern of microlamellae with variable thickness that is similar in all bivalves from the same population (2). The present study shows that even in different populations the specific pattern of each annual increment is similar as long as they have the same temperature regime. The same microgrowth pattern is also found in shells of U. crassus. This indicates that the microgrowth pattern is

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influenced mostly by temperature variations. The number of the microlamellae within one year corresponds with the number of days in the year when the water temperature has been higher than 7°C, which indicates that the microlamellae are daily growth increments. Chemical analyses of the shell have been performed using ICP-MS, Proton Microprobe and Ion Microprobe combining high multielemental capacity and low detection limits with high spatial resolution. These analyses show that there are no major differences in elemental distribution within the shells of the two M. margaritifera populations. In contrast, shells of M. margaritifera and U. crassus from the same river have different chemistry. This suggests that the elemental distribution within the mussel shell is specific for each species as long as they are from unpolluted environments.

(1) Dunca E 1999, Vatten 55: 279-290. (2) Dunca E et al. 2001. Am. Malacol. Bull. 16: 239-

250.

SHELL GROWTH IN JUVENILE MARGARITIFERA MARGARITIFERA FROM

NORTHERN SWEDEN

Dunca, E., Söderberg, H., Norrgrann, O., Mutvei, H., and Schöne, R.B.

(1*, 4) Swedish Museum of Natural History, Department of Palaeozoology, Box 50007, S-10405 Stockholm, Sweden; (1) elena.dunca@nrm.se, (4)

harry.mutvei @nrm.se; (2, 3) Länsstyrelsen Västernorrland, S-871 86

Härnösand, Sweden; (2) Hakan.Soderberg@y.lst.se; (3) Oskar.Norrgrann@y.lst.se;

(5) Institute for Geology and Paleontology , J W Goethe University Frankfurt, Senckenberganlage 32-34, 60325

Frankfurt / Main, Germany.

During the last century, the long-lived freshwater pearl mussel, Margaritifera margaritifera has suffered a serious decline and has been listed as 'vulnerable' by the World Conservation Union. Preliminary monitoring shows that many of the Swedish Margaritifera populations are only composed of large (old) individuals (1), which means that the majority of the populations does not regenerate and will become extinct in time. Consequently, there are general efforts in Sweden to improve environmental conditions for the regeneration of M. margaritifera populations, which are not only important for the biological, ecological and cultural aspects, but also as a tool to understand the environmental history. Shells of this species record

ambient environmental conditions (temperature, water chemistry, pH) during their life as variable annual increments and as variable distribution of chemical elements providing reliable environmental archives (2, 3). The present paper presents the correlation between age and length of M. margaritifera shells from three rivers in northern Sweden, with a focus on juvenile stages (shells smaller than 50 mm). This allows a more precise age estimation of the mussels in the field by measuring the shell length, thus providing a better tool for the monitoring of the mussel populations. The water quality of two rivers, Vattenån River and Kniptjärnsbäcken River, is not affected by human activities.

The shell growth pattern of all the mussels collected from the two unpolluted rivers exhibit a high degree of running similarity. The third river, Maljan River, is limed since 1989 in order to increase the pH of the water. The liming effects are seen as strong growth disturbance lines in all collected shells. Also, the growth rate of these shells shows significant differences in comparison with the nearby unaffected rivers. This demonstrates that M. margaritifera mussels, especially the juvenile stages, are very sensitive to changes of their environment and in order to protect them it is necessary to wisely choose the right measures. [This project is financed by the World Wildlife Fund (WWF)].

(1) Eriksson MOG et al. 1998. Rapport 4887 Naturvårdsverket.

(2) Mutvei, H et al. 1994. Bull. l'Inst. océan., Monaco 13: 163-191.

(3) Dunca, E. 1999. Vatten, 55: 279-290

ENVIRONMENTAL RECONSTRUCTION OF HIGH PRODUCTIVITY MARINE SETTINGS: BIVALVE PALEOECOLOGY OF THE UPPER

CAMPANIAN MISHASH FORMATION, ISRAEL

Edelman-Furstenberg, Y.

Geological Survey of Israel, 30 Malchei Yisrael St., Jerusalem 95501; yael@gsi.gov.il

Factors governing the deposition of sediments rich in silica, organic carbon, and phosphorite in high-productivity (upwelling) marine settings are complex, and the high degree of organic rain to the seafloor and associated anoxia has resulted in these regions being regarded as "benthic dead zones". However, contrary to this stereotype, the Upper Campanian Mishash Formation of Israel, which is one of the most intensive

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and geographically extensive high-productivity regions in the geologic record, contains abundant and diverse benthic macrofauna. I examined the molluscan fossil assemblages of this ancient record to explore gradients in community structure and taphonomic conditions across upwelling seafloors, and to use these features to infer seafloor conditions, especially bottom oxygen levels. Five sections of the Mishash Formation from southern Israel were described. The lower Phosphatic-Carbonate unit of the Formation contains a series of 1-9 meters thick cycles composed of micritic organic-rich carbonates, cherts and porcelanites and diagenetically obliterated carbonate layers; each cycle is capped by a phosphate-bearing shell bed. An upward trend of overall coarsening grain size, increasing fossil abundance and shell packing in each cycle is interpreted as reflecting an increase in bottom oxygen and water energy levels, from quasi-aerobic (water energy levels correlative to below storm wave base) to fully aerobic (above fair-weather wave base). Quantitative macrofaunal analysis was conducted on material collected from each of the main lithologies. Each biofacies of the Mishash is characterized by a specific shelly macrofaunal assemblage and community structure, as well as distinctive lithotype and are consistent with independent ichnofabric and sedimentologic evidence of seafloor conditions during the deposition of the Mishash Formation. Specifically, faunal analysis indicates decreasing species richness and decreasing body size of Caestocorbula together with increasing abundance of deposit-feeding bivalves along an inferred decreasing oxygen gradient. This trend corresponds to closer proximity to the upwelling center or increasing upwelling intensity.

NEW SYSTEMATIC AND BIOSTRATIGRAPHIC DATA ON THE

CENOMANIAN-TURONIAN RADIOLITIDAE (BIVALVIA: HIPPURITOIDEA) OF ABU ROASH, WESTERN DESERT, EGYPT

El Hedeny, M.M.

Geology Department, Faculty of Science, Alexandria University, Moharram Bay 21511, Alexandria, Egypt;

m_elhedeny@yahoo.com

The Rudistae Series of Abu Roash (northwestern Egypt) contains abundant radiolitid bivalves that are described herein in detail. A latest Cenomanian - early Turonian age is assigned to this series. The studied sequence includes Bournonia fourtaui Douvillé 1910, Durania gaensis (Dacqué 1903), Eoradiolites cf. davidsoni (Hill

1893), Eoradiolites liratus (Conrad 1852), Praeradiolites ponsianus (d'Archiac 1835), Radiolites sauvagesi? (d'Hombres-Firmas 1838), Radiolites lewyi Parnes 1987 and Radiolites lusitanicus (Bayle 1857). Among these forms four species are documented for the first time in the studied area. Stratigraphically, the Rudistae Series can be subdivided into three distinct stratigraphic units. They are, from oldest to youngest:

· Unit 1 (uppermost Cenomanian), represented by marls intercalated with a thin limestone bed. The rudist species Eoradiolites cf. davidsoni (Hill 1893) and Eoradiolites liratus (Conrad 1852) are predominant within the upper portion of the marl bed of this unit. This bed may tentatively determine the C/T boundary in this area.

· Unit 2 (lower Turonian), consists mainly of limestones intercalated with thin beds of marls and sandy shales. These deposits frequently contain Praeradiolites ponsianus (d'Archiac 1835), Radiolites lusitanicus (Bayle 1857) and Durania gaensis (Dacqué 1903).

· Unit 3 (lower Turonian), represents the youngest unit in the Rudistae Series. It starts with a rudist-free sandy shale bed. The last limestone bed in this unit contains the thick-shelled radiolitid Durania gaensis (Dacqué 1903) and numerous Bournonia fourtaui Douvillé 1910, Radiolites lewyi Parnes 1987 and Radiolites sauvagesi (d'Hombres-Firmas 1838).

ULTRASTRUCTURAL RELATIONSHIP BETWEEN PRISMATIC AND FOLIATED

LAYERS IN SOME PTERIOMORPH BIVALVES

Esteban-Delgado, F.J., Checa, A.G., Harper, E.M., and Rodríguez-Navarro, A.B.

(1*, 2) Departamento de Estratigrafía y Paleontología, Facultad de Ciencias, Universidad de Granada, Avda.

Fuentenueva s/n, 18071 Granada, Spain; (1*) fjesteb@ugr.es, (2) acheca@ugr.es;

(3) Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ,

UK; emh21@cam.ac.uk; (4) Departamento de Mineralogía y Petrología,

Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, 18071 Granada, Spain; anava@ugr.es

The study of bivalve microstructures has attracted the interest of researchers for decades particularly in the study of phylogenetic relationships and their mechanical properties. Prismatic microstructures (either aragonitic

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or calcitic) are some of the most widespread. Calcitic prisms are frequent in Pteriomorphia, where many groups have shells with an external prismatic layer, which is underlain either by an aragonitic (nacreous or crossed lamellar) or calcitic (foliated) layer. Prismatic layers have great flexibility because of their high organic content, and their ventral extension beyond the inner shell layers allows a tight seal when valves are shut. In pterioids the prismatic flexible margin appears in both valves, the internal layer being nacreous. In ostreids, anomiids and propeamussiids the prismatic layer is commonly restricted to the right valve with the left valve margin composed of rigid foliated layer. In other groups, e.g. limids, spondylids and pectinids, the prismatic layer is completely or almost completely absent with foliated rigid margins in both valves. Since the relationships between these different arrangements are unknown, we have undertaken a study of the ultrastructure of the calcitic layers in some representative members of the Pteriomorphia using scanning electron microscopy and diffracting techniques.

Our results indicate that in Pterioida prisms are massive and lack any recognizable ultrastructure. In contrast, in those groups with an underlying calcitic foliated layer (ostreids, anomiids, propeamussiids and pectinids), the prisms of the external layer are composed of calcitic laths. These laths are indistinguishable from the laths of the foliated layer. Thus, the prismatic and the foliated layer consist of the same structural elements, and the only difference is the presence of organic envelopes delineating the prisms. We therefore assume that the foliated layer has arisen from "foliated" prisms and that the development of rigid shell margins (either in one or both valves) in several groups of bivalves was achieved by replacing the flexible external prismatic layer by its derived foliated microstructure.

EARLY ONTOGENETIC FEATURES OF MYTILUS TROSSULUS AND CRENOMYTILUS GRAYANUS (BIVALVIA: MYTILIDAE) AND

THEIR USEFULNESS FOR THE MYTILID TAXONOMY

Evseev, G.A., Kolotukhina, N.K., and Semenikhina, O.Y.

A.V.Zhirmunsky Institute of Marine Biology, Far Eastern Branch of Russian Academy of Sciences,

Vladivostok 690041, Russia; (1) evseev@mail.primorye.ru; (3) oja@mail.primorye.ru

The current taxonomic classifications of recent Mytilidae as well as Bivalvia on the whole are largely based on morphological features of adult specimens. Juvenile morphological characters are sometimes included as an extension for taxonomic identifications but are not used for phylogenetic analyses, and larval characters are generally entirely ignored. This can be mainly explained by the absence of common features in both larvae and adults. However, our morphogenetic studies of two mussel species from the northwestern Pacific, Mytilus trossulus and Crenomytilus grayanus, and comparisons with other mytilid taxa reveal that morphological traits of larvae and juveniles are taxonomically and phylogenetically indicative at various ranks within the Mytilidae.

Important larval features of lower rank include: (a) general shell outlines; (b) dimensions of prodissoconchs I and II; (c) shape of umbo and location of its anterior margin relative to anterior provincular denticles; (d) color of central or marginal parts of PD-II; (e) probably, dimensions of eye-spot. At the same time, larval shells generally bear common morphological structures as PD-I and/or PD-II, three types of provincular denticles, and the primary ligament pit, peculiarities of which can be taxonomically considered as features specifying the highest classification ranks.

In the juvenile stage, the following characters are believed to indicate species or genus rank: (a) peculiarities of posterior lateral teeth of dysodont type; (b) dissoconch sculpture; (c) outlines, topology, and configuration of adductor and retractor scars; (d) sometimes, porosity of organo-carbonate layer connecting the secondary ligament resilium with dissoconch shell. At the same time, primary and secondary lateral teeth, which are typical characters of higher taxonomic categories in Perna, Modiolus, Septifer, and other taxa of Mytilidae, were not revealed in the species studied. Thus, the early ontogenetic features of some mytilid species can not only supplement the taxonomic characters of the family and detail descriptions of its taxa but also significantly increase our knowledge of homology and ranks of morphological features used for the bivalve taxonomy. [Funded by grant 06-III-?-06-164 from the Presidium of FEB RAS.]

A NEW SCENARIO FOR THE EARLY EVOLUTION OF THE BIVALVIA

Fang, Z.

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Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences. Nanjing, 210008, The

Peoples' Republic of China; zjfang@nigpas.ac.cn

A comparison between Cambrian 'archetype' bivalves and Ordovician 'modern-type' bivalves indicates that the morphological adaptations to infaunal life in the Bivalvia did not evolve until the Ordovician. There must be an adaptive barrier to the infaunal adaptive zone for Cambrian 'archetype' bivalves, because most of their organs are still in their incipient evolutionary stages. A new scenario for the early evolution of the class Bivalvia is advanced herein based on the integration of a wide variety of evidence concerning bivalves, including morphological features, ontogenetic trajectory, benthic environment and lithologic setting, so as to explain reasonably why the initial explosive radiation of bivalves in the Early Ordovician followed a long-term macroevolutionary lag since their first appearance during the Cambrian explosion. The early evolution of the Bivalvia can be divided into three phases: (a) the origination and macroevolutionary lag phase in the Early and Middle Cambrian; (b) the crisis phase in the Late Cambrian; and (3) the Ordovician radiation phase, which can be subdivided into two radiation pulses or intervals. It is the Cambrian substrate revolution that caused a transformation of shallow subtidal seafloors from more coherent Neoproterozoic-style matgrounds to soupier Phanerozoic-style mixgrounds, thus compelling Cambrian 'archetype' bivalves to sink into the infaunal realm and to adapt themselves to the development of the mixed layer in siliciclastic soft substrate environments. As a result, Cambrian 'archetype' bivalves entered a tight bottleneck and became extinct while the latest common ancestor of 'modern-type' bivalves originated from a certain founder population somewhere in the Gondwanan shelf seas. The rapidly evolving founder population may be the place of origin of evolutionary novelties and it became the starting point of the evolution of 'modern-type' bivalves. The bivalve die of 'modern-type' was cast during the Ordovician, when all principal clades and all four principal life-habit groups underwent initial development. A series of morphological innovations, especially the evolution of the muscular hydraulic foot with burrowing adaptations, byssus, and feeding gill, are responsible for the initial adaptive radiation. It is these morphological innovations that provide evolutionary access to the new adaptive zone for bivalves.

ANALYSIS OF 16S rRNA AND 12S rRNA MITOCHONDRIAL GENES IN DIFFERENT

EUROPEAN LOCALITIES OF AEQUIPECTEN OPERCULARIS

Fernández-Moreno, M., Martínez-Lage, A., Méndez Felpeto, J., and González-Tizón, A.

Dpto. de Biología Celular y Molecular, Universidade da Coruña, A Zapateira s/n, 15071 La Coruña, Spain;

(4*) hakuna@udc.es

The phylogenetic relationships within the family Pectinidae has been explored using different molecular markers (1-4). Often, mitochondrial DNA resulted to be more suitable than other markers to construct and resolve phylogenies. Mitochondrial DNA (mtDNA) is a very useful molecular marker in studies of genetic diversity, population genetics, phylogeography, and phylogenetic reconstruction (5) because of its mode of inheritance and rapid rate of evolution. In bivalve molluscs different regions of the mtDNA have been analysed.

In the pectinid Aequipecten opercularis (Bivalvia, Pteriomorphia) the partial amplification of 16S rRNA and 12S rRNA mitochondrial genes yielded fragments of ~482 bp and ~432 bp, respectively. The individuals analysed came from three different European localities: Donegal (North of Ireland), Fuengirola (Málaga, S Spain) and El Grove (Galicia, N Spain). Analysis of base composition showed AT richness, as usual in mitochondrial genomes. The alignment of nucleotide sequences of these genes displayed no difference among the individuals analysed. The analysis of the Restriction Fragments Lenght Polymorphisms (RFLPs) obtained after digestion of the 16S rRNA fragments obtained from 34 individuals corresponding to each locality with Acs I, Alu I, Hae III and Hinf I endonucleases, allowed us to establish six different haplotypes. Aequipecten opercularis from El Grove showed the highest number of haplotypes, while Irish locality displayed three different haplotypes, and Málaga locality resulted to be monomorphic. The haplotype 1 was the most common in all the localities, while the rest of haplotypes appeared in a low proportion (only in one individual per locality). The phylogenetic analysis was carried out using other species belonging to the same family. [Funded by: Xunta de Galicia research project (AGL2003-07430). We are grateful to Mr. Jose García Gil for his technical assistance].

(1) Canapa et al., 1999. J. Mol. Evol. 48: 463-468. (2) Canapa et al., 2000. J. Mol. Evol. 50: 93-97. (3) Matusumoto and Hayami, 2000. J. Moll. Stud. 66:

477-488. (4) Barucca et al., 2004. Mol. Phylogenet. Evol. 31:

89-95.

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(5) Avise et al., 1987. Annu. Rev. Ecol. Syst. 18: 489-522.

THE FRESHWATER MUSSEL MARGARITIFERA MARGARITIFERA (L.) IN

GALICIA, NW SPAIN - PRELIMINARY STUDY IN EO AND MASMA RIVERS

Fernández, C., Outeiro, A., Ondina, P., Amaro, R., and San Miguel, E.

(1, 4, 5) Dpto. Xenética. Facultade de Veterinaria. 27002 Lugo. Spain.

(2, 3*) Dpto. Bioloxía Animal. Facultade de Veterinaria. 27002 Lugo. Spain

Margaritifera margaritifera (L.) has become scarce or threatened throughout most of its range of distribution and is considered one of the most endangered freshwater mussels of Europe. Its southernmost range is the northwestern Iberian Peninsula where it has been cited in a few rivers of Asturias, Zamora and Salamanca (1-3) and recently also from Portugal (4). In a preliminary study on the actual situation of this species in Galicia, we could confirm the presence of the previously described populations and report newly discovered populations in about twenty rivers (5). These results place Galicia in a critical area to apply conservation measurements to preserve M. margaritifera in Europe.

We also carried out an intensive study in the rivers Eo and Masma with different hydrological and ecological characters in order to evaluate the functional situation of the populations and the ecological factors that may be influencing them. We used adaptive cluster sampling methodology, which was specifically designed to study aggregative distributions. From a statistical perspective, this sampling method is appealing because it is efficient for rare populations (6). We used the Morisita Index to calculate the aggregation level of the populations within both rivers. We present here the densities of the studied sections and the frequency distributions of the body length of the specimens to evaluate the age structure of the populations.

(1) Álvarez-Claudio C, García-Roves P, Ocharán R, et al. 2000, Aquatic Conservation: Marine and Freshwater Ecosistems, 10: 93-102.

(2) Morales J, Negro AI, Lizana M, Martinez A and Palacios J 2004, Aquatic Conservation: Marine and Freshwater Ecosystems, 14: 587-596.

(3) Velasco JC, Araujo R, Bueno R, Laguna A 2002, Iberus, 20: 1-10.

(4) Reis J. 2003, Biological Conservation, 114: 447-452.

(5) San Miguel E, Monserrat S, Fernández C, et al. 2004, Canadian Journal of Zoology, 82: 1370-1379.

(6) Thompson JD and Seber GAF 1996, Adaptive sampling, Wiley, 288 pp.

ISOLATION AND CHARACTERIZATION OF POLYMORPHIC MICROSATELLITE LOCI IN

THE RAZOR CLAM SOLEN MARGINATUS

Francisco-Candeira, M., Varela, M., González-Tizón, A., and Martínez-Lage, A.

Departamento de Biología Celular y Molecular, Universidade da Coruña, Campus de A Zapateira s/n,

E-15071 A Coruña, Spain. (4*) andres@udc.es

Microsatellites or SSR (Simple Sequence Repeat) are a class of repetitive DNA sequences widely distributed in eukaryote genomes. In this study we try to search for microsatellite loci in the razor clam Solen marginatus (Bivalvia, Solenidae). This species is distributed along the European Atlantic coast, from Norway to Spain, in some parts of the Mediterranean and northwest Africa. Microsatellite loci were isolated using two different approaches: a) the construction of a enriched library and b) from sequences of Inter Simple Sequence Repeat (ISSR) markers (1). Two libraries enriched for tri- and dinucleotide repeat motifs, (CTT)6 and (GT)10, were constructed using genomic DNA isolated from muscle of one individual. The digested fragments were hybridized with biotinylated repeat oligos, and then extracted using streptavidin-coated magnetic beads. The ISSR markers were generated from nucleotide sequences located between two microsatellite priming sites using the following anchored primers: HVG (TG)7, KRV (CT)6, G(CT)9, YG(CT)9, YG (GA)9 and YG(CA)9 (2).

A total of eight primer pairs were developed using Gene Fischer (3) to amplify eight internal microsatellites. An initial screening of the eight primer pairs was evaluated for robust amplification and polymorphism in 15 individuals of Solen marginatus from Redondela (NW Spain) using an Agilent 2100 Electrophoresis Bioanalyzer (Agilent technologies). One primer pair resulted to be monomorphic. Four primer pairs failed to amplify in all individuals, and three produced a clear polymorphic banding pattern. Characteristics of the polymorphic loci were determined using GENEPOP version 3.3 (4). The number of alleles at each locus ranged from five to 10 and observed heterocigosities ranged from 0.1667 to 0.9545. No loci showed

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significant linkage disequilibrium (P<0.05). These first three polymorphic microsatellite markers presented here are expected to be useful for future studies on the population structure of Solen marginatus.

(1) Fisher PJ et al. 1996, Nucleic Acids Research 24: 4369-4371.

(2) Zietkiewicz E et al. 1994, Genomics 20:176-183. (3) http://bibiserv.techfak.uni-bielefeld.de/

genefisher/ (4) Raymond M and Rousset F 2004, GENEPOP

(version 3.4): population genetics software for exact test and ecumenicism.

THE EFFECTS OF A TOXIC STRAIN OF KARLODINIUM VENEFICUM ON THE BLUE

MUSSEL MYTILUS EDULIS

Galimany, E., Pipe, R.K., Jutson, M., and Ramón, M.

(1*,4) Centre d'Aqüicultura (IRTA), Crta. Poble Nou s/n St. Carles de la Ràpita 43540, Spain; (1)

eva.galimany@irta.es; (2, 3) Marine Biological Association, Citadell Hill

Plymouth PL1 2PB, UK

Blue mussels, Mytilus edulis, were collected from Whitsand Bay, Cornwall (UK) and exposed to a toxic dinoflagellate alga Karlodinium veneficum (PLY # 103). Toxic K. veneficum are found globally. The karlotoxins isolated from the alga are polyhydroxy-polyenes that are haemolytic and act by increasing the ionic permeability of cell membranes. Algal blooms of the species can occur naturally and the karlotoxins can affect a variety of animals. The effects of exposure to Karlodinium veneficum on immune function and histopathology were investigated. Mussels were acclimatized for one day and samples were taken before exposure and after 3 and 6 days exposure to the toxic alga. Assays for immune function included total and differential cells counts, phagocytosis, and release of reactive oxygen species. Histology was carried out on digestive gland and mantle tissues.

Results showed significant effects on phagocytosis and release of reactive oxygen species following 6 days exposure. There were no significant effects on total cell counts. However differential cell counts did show significant effects including apparent degranulation of the eosinophylic granular cells after 6 days exposure to the toxic alga. Histology on the digestive gland showed an ingestion of the toxic alga and histology on mantle tissue showed a haemocyte invasion after 3 days of exposure. All mussels were fully ripe and produced

faeces but no pseudofaeces indicating that algae were not rejected prior ingestion.

PRELIMINARY DATA ON THE DISTRIBUTION AND DENSITY OF PINNA

NOBILIS AND PINNA RUDIS IN THE COLUMBRETES ISLANDS MARINE

RESERVE (WESTERN MEDITERRANEAN, SPAIN)

García-March, J.R. and Kersting, D.K.

(1*) Marine Biology Laboratory, University of Valencia, C/Dr. Moliner 50, 46100 Burjassot (Valencia), Spain; jose.r.garcia-march@uv.es

(2) Columbretes Islands Marine Reserve, SGPM-Tragsa, C/ Músico Perfecto Artola, 6A, 12003 Castelló,

Spain; dkerstin@tragsa.es

The Columbretes Islands Marine Reserve encircles a volcanic archipelago situated 30 nautical miles off the coast of Castelló, Spain. The reserve is managed by the Spanish Fishing Authority, Secretaría General de Pesca Marítima. These are the preliminary results of density and distribution of Pinna nobilis and P. rudis in the marine reserve at depths above 40 m. An area of 3675 m^2 has been surveyed and a total number of 66 specimens (55 P. nobilis and 11 P. rudis) have been censed showing a mean density of 1.5 P. nobilis/100m^2 and 0.3 P. rudis/100m^2. In order to study the population dynamics, recruitment, mortality and growth, 44 of the 66 individuals (39 P. nobilis and 5 P. rudis) were tagged and their position recorded in seven different areas ranging from 100 to 314 m^2.

The survey indicates that both species are ubiquitous around the islands. They inhabit diverse substrates varying from Cymodocea nodosa meadows to boulder fields. Pinna nobilis has been found to be more common in Cymodocea meadows and in biodetritic and marl beds. The highest density is found in the Cymodocea meadow of El Carallot islet with maximum concentrations of 16 P. nobilis and 2 P. rudis/100m^2. Reasons explaining these aggregations are being researched, since their characterization seems essential to understand the ecology of both species. The mean density of Pinna nobilis obtained in Columbretes is higher than those reported in other marine reserves of the western Mediterranean: 1 specimen/100m^2 in Port Cross (France) (1) and the range from 0 to 3.5 specimen/100 m^2 given for Scandola (France) (2). However it is smaller than the density estimated for the Adriatic (9 specimen/100m^2) (3) and in Mljet National

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Park (Croatia) (ranging from 2 to 20 specimen/100m^2) (4).

(1) Combelles S et al. 1986, Sci Rep Port-Cros natl Park 12: 29-43.

(2) Medioni E, Vicente N. 2003, Mem Inst Oceanogr Paul Ricard pp 43-48.

(3) Zavodnik D et al. 1991, In: Les Espèces Marines à Protéger en Méditerranée (Boudouresque CF et al. eds.), Gis Posidonie publication, Marseille, pp 169-178.

(4) Siletic T 2003. Sci Mar 67(1): 91-98.

POLYMORPHISM AND SHELL RESHAPING IN PINNA NOBILIS L., 1758: THE

RELIABILITY OF SHELL DIMENSIONS FOR ONTOGENETIC AGE AND POPULATION

GROWTH RATE ESTIMATES

García-March, J.R. and Márquez-Aliaga, A.

(1*) Marine Biology Laboratory, University of Valencia. C/Dr. Moliner 46100 Burjassot (Valencia),

Spain; jose.r.garcia-march@uv.es (2) Instituto Cavanilles de Biodiversidad y Biología

Evolutiva. Departamento de Geología, Universitat de Valencia. Campus de Burjassot. C/ Dr. Moliner 50,

46100 Burjassot (Valencia) Spain; ana.marquez@uv.es

Generally, the age of Pinna nobilis specimens and population growth rates (PGR) are estimated from maximum shell length measured from the umbo. However, shells show different morphologies, mainly straight and wide, straight and narrow, and combed, whose originating factors are still unknown. We wanted to know how reliable shell maximum length is as an estimator of age and PGR and studied the morphology of 178 specimens, collected during the last decade, under this aspect (1).

The pinnid shells were found to undergo a continuous process of abrasion and reconstruction (termed reshaping herein) which made us hypothesise that this is the cause of the observed polymorphism. All valves show signs of abrasion in their dorsal, ventral and anterior borders, as well as the external surface. This abrasion, more important along the anterior border, eliminates older shell and brings younger shell deposits in contact with the environment. The individuals counteract this abrasion mainly by posteriorward migration of the soft tissues which leads to the reconstruction of the acute anterior apex as well as to the formation of new ligament layers (2). The fan shell morphology is thus maintained regardless of apex loss;

however, the morphology resulting from this reshaping process depends on the quantity and importance of shell abrasion and reconstruction. In this regard, we have observed that all straight and wide specimens show a heavy injury of the shell apex (an extreme form of abrasion), an accelerated migration of the tissues and an abruptly reconstructed apex. Our data indicate that the other morphologies are similarly influenced by the different degrees of abrasion. It therefore appears that the relation between shell proportion and age is different for each morphology. In consequence, the exclusive use of maximum shell length (or any other shell dimension) generates strongly biassed age and PGR estimates. For more reliable estimates it appears fundamental to acquire a better knowledge on the relationship between the amount of shell reshaping and morphology.

(1) García-March JR, in press, Aportaciones al conocimiento de la biología de Pinna nobilis Linneo, 1758 (Mollusca: Bivalvia) en el litoral mediterráneo ibérico, Publication Service of the University of Valencia, 332 pp.

(2) García-March, et al. in press, J. Paleontol.

IN-SITU SHELL GAPING BEHAVIOUR OF PINNA NOBILIS L., 1758

García-March, J.R., Sanchis-Solsona, M.Á., and García-Carrascosa, A.M.

(1*, 2, 3) Marine Biology Laboratory, University of Valencia. C/Dr. Moliner 46100 Burjassot (Valencia),

Spain; (1) jose.r.garcia-march@uv.es

Valve activity is closely related to physiological processes in bivalve molluscs so that the study of the former provides information on breathing, nutrition, responses to stress, etc. However, laboratory conditions can alter the natural rhythms regulated by biological clocks entrained by environmental variations. For this reason, to study Pinna nobilis nutrition behaviour we decided to make an experiment of shell gaping in-situ by monitoring for the first time a marine subtidal bivalve mollusc in its natural environment. To achieve this, we designed and built a new appliance for which we collaborated with the electronic engineer and co-author Sanchis-Solsona (MASS). The new device should meet 5 prerequisites: i) autonomy, ii) low energy consumption, iii) standardized sensors for every experiment should detect movements of few millimetres, iv) it should not interfere with valve activity, and v) it should be small and waterproof. Our device contains two main components: the electronic system and the sensor. The electronic system itself consists of a clock, a control system and EEPROM

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memories; the sensor is formed by four magnetic relays (no energy supply required), which are encapsulated and screwed on two supports pasted on each valve of the studied specimens. The electronic system remains in a standby mode until the animals move the valves in which case the position of the sensor and the date are recorded. Four small AA batteries provide energy supply for up to three months of survey. The animals are not expected to notice the sensors because Pinna nobilis individuals are used to have the shells completely overgrown by large epibionts. The activity of ten individuals was studied for periods of three to 21 days. Each experiment was performed simultaneously in two individuals in order to permit paired comparisons.

The results demonstrate the existence of marked circadian and circalunar rhythms in shell gaping. Basically, the individuals shut their valves after sunset and open them with sunrise. However, they also open the valves during clear nights with sufficient Moon light (more than 50% of the disc illuminated). In lieu of these observations, P. nobilis shell gaping behaviour can be defined according to four different trends: the two most common, i) night closing related with sunset and ii) night opening related with the position and degree of illumination of the Moon, and two uncommon, iii) day closing and iv) night opening with no visible Moon. The success of our little invention will allow us to perform comparisons of in-situ and in-vitro behaviour, pumping rates, breathing and particle depletion rate.

CONDITION OF FRESHWATER MUSSELS HELD IN REFUGIA AT THE WHITE

SULPHUR SPRINGS NATIONAL FISH HATCHERY (WSSNFH), WEST

VIRGINIA: IS THERE A FUTURE FOR LONG-TERM MUSSEL REFUGIA?

Gatenby, C.M., Patterson, M.A., Devers, J.B., and Kreeger, D.A.

(1*, 2, 3) United States Fish and Wildlife Service, 400 E. Main Street, White Sulphur Springs, West Virginia, United States 24986; (1) c atherine_gatenby@fws.gov (4) (Daniella Kreeger) Partnership for the Delaware Estuary, 110 South Poplar Street, Wilmington, DE

19801

The US Fish and Wildlife Service established a refugium at the WSSNFH for endangered freshwater mussels residing in harms way of various in-stream activities such as those associated with road construction, or contaminant spills. A refugium was also

viewed necessary to preserving biologically significant populations threatened by exotic species and habitat loss. Approximately 3600 mussels comprising 15 species were salvaged in 2004 and in 2005 from under a bridge in the Allegheny River, scheduled for demolition and reconstruction in 2007. Approximately 1500 mussels (5 species, including 2 endangered) were relocated to WSSNFH where they will remain up to 5 years. Non-lethal and lethal measures of physiological activity were used to monitor condition of common mussels; non-lethal measures were used to monitor condition in endangered species of mussels. In August, 2005 a diet quality feeding study was conducted to evaluate the use of cultured algal diets and wild seston diets for maintaining mussels in long-term refugia.

From 2004 to 2005, all species showed significant declines in condition over time; however, the seasonal condition of Elliptio dilatata was not significantly different from wild E. dilatata in September, 2005. Indeed, after one year in captivity, short-term brooders showed higher survival than long-term brooders. Modifications made in 2005 to improve food delivery and flow rates in our culture systems appear to have facilitated optimal feeding behavior. Mussels show significantly higher condition and have maintained improved condition for 8 months. Additionally, there is no significant difference in condition between mussels fed wild seston and algae and mussels fed only a cultured algal diet. Survival of endangered mussels brought into captivity in spring 2005 ranges 93%-100% for Epioblasma t. rangiana and Pleurobema clava. Captive care protocols developed from this effort will be available as conservation tools in the future for mitigating loss of a resource due to in-stream activities, and for preventing the extinction of rare mussels.

SHELL MICROSTRUCTURE OF MYTILOIDS (BIVALVIA)

Génio, L., Kiel, S., Little, C.T.S., Grahame, J., and Cunha, M.R.

(1*, 3, 4) Earth and Biosphere Institute, Leeds, LS2 9JT, UK

(2) Dept. of Paleobiology, Smithsonian Natural History Museum, Washington DC, 20013, USA

(5) CESAM - Centro de Estudos do Ambiente e do Mar, Aveiro, 3810-193, Portugal

Mytiloids are important elements of deep-sea chemosynthetic ecosystems, such as hydrothermal vents, hydrocarbon seeps and sunken dead whales and wood (1), but their phylogenies are far from being

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resolved. Although certain physiological adaptations occur in chemosynthesis based organisms, some morphological characteristics show high similarity with those of the phylogenetic group to which these organisms belong, rather than being affected by their particular environmental conditions (1, 2, and 3). The aim of this study is to review the shell microstructural details of mytiloids for phylogenetic analysis of the chemosynthetic representatives.

The outer shell layer of mytiloids shows high variability in microstructure and also in mineralogy (4). Different structures may occur in the outer shell, which can be entirely aragonitic or composed of an outer calcitic sublayer and an inner aragonitic sublayer (4). Preliminary results based on Scanning Electron Microscopy (SEM) of shell microstructure of 16 species from 13 mytiloids genera are presented here. Most of the specimens investigated so far are from shallow-water sites and the revision of their shell microstructures will be important for the future work with deep-sea chemosynthetic mussels.

(1) Van Dover CL (ed.) 2000, The Ecology of Deep-Sea Hydrothermal Vents, Princeton University Press, 424 pp.

(2) Kiel S 2004, Malacologia, 46 (1): 169-183. (3) Roux M et al. 1985, In: The Hydrothermal Vents of

the East Pacific: An Overview (Jones ML (ed.). Bulletin of the Biological Society of Washington, No. 6, 211-221.

(4) Carter JG 1990, In: Skeletal biomineralization: patterns, processes and evolutionary trends (Carter JG, ed.). Van Nostrand Reinhold, 136-296.

TAPHONOMY OF LATE CRETACEOUS FRESHWATER BIVALVES FROM BAURU GROUP, BAURU BASIN (MONTE ALTO

COUNTY, SÃO PAULO STATE, BRAZIL): PALEOENVIRONMENTAL IMPLICATIONS

Ghilardi, R.P., D´Agosta, F.C.P., Tavares, S.A.S., and Campos, A.C.d.A.

(1*, 2) DCB-FC-UNESP, Av. Luiz E. Carrijo Coube, s/n, Bauru, SP, Brasil, CEP 17033-360; (1*)

ghilardi@fc.unesp.br (3,4) Museu de Paleontologia, Praça do Centenário,

Monte Alto, SP, Brasil, CEP 15910-000

Sediments of the Upper Cretaceous Bauru Group (Bauru Basin, Brasil) are famous for their rich vertebrate fossil content (e.g. crocodiliomorphs, chelonids, amphibians, dinosaurids). However, they also

contain a considerable amount of bivalves representing the genera Anodontites, Taxodontites, Itaimbea, Monocondylaea, Musculium, Diplodon, Sancticarolis and Florenceia. Since 1974 very little has been published on these bivalves and taphonomical and paleoecological approaches are lacking. Consequently, little is known on live conditions, energy of the environment or ecological relationships. According to the presently most accepted view, the bivalves lived under freshwater conditions in fluvial or lake environments.

We here report on a so far unknown bivalve fossil site, the Água Limpa outcrop (S 21° 16` 45`` W 48° 32` 20``) in the Monte Alto County (São Paulo State) characterised by a great number of fragmented shells within the typical coarse sandstone of Bauru Group. A systematic classification was not possible, but the disarticulation rate (100%), fragmentation (80%), chaotic arrangement and lack of shells in life position of the 42 shells suggest transport under high energy conditions (probably fluvial) before burial.

NUCULOIDEAN TRACE FOSSILS IN THE SHALLOW MARINE MIOCENE OF THE

VALLÈS- PENEDÈS BASIN (NE IBERIAN PENINSULA)

Gibert, J.M. and Domènech, R.

Departament d'Estratigrafia, Paleontologia i Geociències Marines, Universitat de Barcelona, Martí

Franquès s/n, 08028 Barcelona, Spain; (1) jmdegibert@ub.edu, (2*) rosa.domenech@ub.edu

Bivalves are among the most abundant fossils found in the geologic record. Nevertheless, traces of their activity are more rarely found. Bioerosion (hard-substrate) traces are relatively common in fossil rocky shore or skeletal substrates, while bioturbation (soft-substrate) trace fossils, although known since the Palaeozoic, are less frequent. The latter are represented by the ichnogenera (trace fossil genera) Lockeia and Protovirgularia. The first is an almond-shaped resting trace, while Protovirgularia is a chevron-shaped crawling trail produced endogenically (below the sediment surface). The Langhian (middle Miocene) deposits of the Vallès-Penedès Basin have provided some specimens of Protovirgularia dicotoma in two different localities. In both cases, the trace fossils are found in heterolithic (sandstone/mudstone) facies deposited in a bay setting. They are preserved as epirelieves (that is, on top of sandstone beds), and occur

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together with irregular-echinoid and worm-produced burrows. The assignation of the traces to a particular bivalve taxon is not an easy task. Fossil shells are not abundant in the outcrops where the trace fossils are found, probably owing to dissolution of aragonite skeletons. Nevertheless, the chevron pattern of the trails allows their attribution to protobranchs, which bear a cleft foot. Among protobranchs, only the endobenthic deposit-feeding nuculoideans are rather mobile in search of food particles. They anchor alternatively the cleft foot and the shell, while pulling forward the shell when the foot is fixed, and pushing forward the foot when the shell is anchored. This rocking movement originates the succesive chevron-shaped marks of the trail. Despite the preservational biases existing in the fossil record of aragonitic shells in the Vallès-Penedès, several species of Nuculidae and Nuculanidae are known. They include Nucula nitidosa, Nucula placentina, Nuculana (Lembulus) emarginata, Nuculana (Lembulus) pella, Ledella aff. messanensis and some other, still unidentified, species of these three genera. It is likely that one or several of these species were the trace makers of Protovirgularia dicotoma. Scaphopods, which also bear cleft feet, cannot be completely ruled out as potential producers, although they are less active burrowers and, additionally, no fossil material is known from the Vallès-Penedès basin despite extensive study.

A MULTI-LOCUS APPROACH TO BIVALVE PHYLOGENY

Giribet, G.

Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard

University, Cambridge, MA 02138, USA

Although bivalve molecular systematics studies have been available for more than a decade and in many ways bivalve systematists have made important contributions to the more general fields of systematics and evolutionary biology, multi- locus approaches to study the phylogeny of the whole Bivalvia are rare. Also, no analysis has yet included all bivalve superfamilies or families. Here I will present a new study on bivalve phylogenetics based on molecular characters (up to more than 6 Kb per complete taxon) for nearly 90% of bivalve families, and including representatives for all superfamilies. The data are analyzed in a multiprocessor cluster using direct optimization algorithms and following a sensitivity analysis approach. Results of this new analysis, which include the largest molecular dataset ever assembled for any molluscan group are

discussed, and a new system for the molluscan class Bivalvia is proposed.

SPECIES DELIMITATION AND PHYLOGEOGRAPHY OF NEOTRIGONIA SP.

IN SOUTHERN AUSTRALIAN SEAS

Glavinic, A., Rouse, G., and Benkendorff, K.

Flinders University, School Of Biology , Po Box 2100, Adelaide 5000 SA

The distribution and taxonomy of the genus Neotrigonia from Southern Australia is reviewed. Maximum parsimony based analysis of mitochondrial COI and nuclear ITS genes reveals that there is a single species ranging across South Australia, Victoria and Tasmania. This suggests that N. bednalli is a junior synonym of N. margaritacea. Population genetics analysis of the Neotrigonia margaritacea COI gene, in five different populations located hundreds of kilometres apart, revealed insights into genealogical pathways among haplotypes. Highest haplotype diversity was recorded from the Port Lincoln (South Australian) population. Haplotyope variations across the range are discussed in terms of estimated population sizes, larval dispersal and geographical barriers due to water movement.

MONTACUTIDAE ON THE NORTH ATLANTIC SEAMOUNTS

Gofas, S. and Salas, C.

Departamento de Biología Animal, Facultad de Ciencias, E29071 Málaga, Spain

Bivalves are generally poorly represented on oceanic seamounts because the scarcity of soft bottoms leaves little space for burrowing species, and because the scarcity of planktic biomass makes filter-feeding inappropriate. The best represented families on the seamounts are the Arcoidea, the Pectinoidea, Verticordiidae and Cuspidariidae. The Montacutidae are yet the best represented family of the Eulamellibranchia, possibly in connection with their feeding habits on the mucous secretions of their hosts. This study is part of an ongoing survey of the benthic fauna on seamounts of the Northeast Atlantic, based on the two Seamont cruises: on the Lusitanian group of seamounts (Gorringe, Ampère, Josephine and Seine) situated between Portugal and Madeira, and on the Meteor group

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(Great Meteor, Hyères, Irving, Plato, Atlantis) situated south of the Azores.

The Montacutidae are a family of small bivalves that live in association with a variety of benthic invertebrates, most commonly with echinoderms. The two common montacutid species on the seamounts were hitherto considered as extremely rare, and were seldom reported after their original description. These are Mysella pellucida originally described from the Adventure Bank in the strait of Sicily, and Mysella ovata, described originally from off SW Portugal. Mysella ovata is found from 200 to 500 m depth on both groups of seamounts, whereas M. pellucida was only found on the Lusitanian group. Both species are unambiguously distinguished from the predominant species of the mainland shelf, M. bidentata by their large prodissoconchs tinged with brown, by their different outlines and by details of the hinge. The traditional generic allocation of all these species to the genus Mysella should be reconsidered, and possibly there is a need for a new genus. The small prodissoconch 1 in M. ovata and M. pellucida indicate for these species a planktotrophic development, which is consistent with their widespread occurrence on the seamounts. The Canarian and Madeiran species M. triangularis was not found on the seamounts, probably because it lacks its interdidal or very shallow habitat.

STABLE ISOTOPES (C, O) OF THE PECTINID PALLIOLUM EXCISUM FROM THE LOWER PLIOCENE OF THE ASILAH BASIN

(NW MOROCCO)

González Delgado, J.A., Armenteros, I., Civis, J., and Rico, A.

Dpt. Geología. Facultad de Ciencias. Universidad de Salamanca, Spain; angel@usal.es

The Asilah basin is a small marine siliciclastic basin ca. 30 km south of Tanger in northwest Morocco. Its sediments are predominantly of Early Pliocene age (Blow´s biozone N-19, Upper Zanclean) (1). The construction (2005) of the Highway Tanger-Rabat has provided a new representative outcrop near Oued Lalhou consisting of a 20 m thick alternation of muddy sands - highly bioturbated by Thalassinoides and Gyrolithes - and more cemented sandy levels rich in bivalve shells; some levels show horizontal lamination and ripple cross-lamination. Bivalves are represented by shell concentrations of articulated Pinna, large Ostrea lamellosa, Acanthocardia paucicostata, Modiolus

adriaticus, Pecten and Palliolum excisum. This latter calcitic-foliated pectinid is present in all stratigraphic levels of the section and was used for a stable C and O isotope analysis for additional palaoenvironmental information. Shells were micro-drilled longitudinally to obtain an average life span of the mollusc. Analytical precision of the samples was 0,02% PDB for carbon, and 0,04% PDB for oxygen.

In the lower levels, delta-13C values range from 0,10 to 1,24 ‰, and delta-18O (PDB) values from 0,84 to 1,75 ‰. Oxygen values can reflect changes up to 4ºC in the sea surface temperature where the bivalves grew. However, in the upper levels, both delta-13C and delta-18O are lighter (between -1,57 and -4,9 ‰, and between 0,13 and -1,5 ‰, respectively) which is attributed to diagenetic alterations due to soil and freshwater influence on the upper profile. The isotopic results in the lower levels are very similar to those obtained for the same taxon from the "Casa del Pino" outcrop in Huelva, which belongs to the Lower Pliocene of the Guadalquivir basin, where the delta-13C values range from 0,16 to 0,99 ‰, and the delta-18O values from 0,96 to 1,8 ‰.

(1) Gonzalez Delgado JA et al 2002, Interim-Colloquium R.C.A.N.S. Salamanca, Abstracts, 192-193 (with references)

A MOLECULAR APPROACH TO THE STUDY OF A MUSSEL (MYTILUS) HYBRID ZONE ON

THE WEST COAST OF IRELAND

Gosling, E. and Coghlan, B.

(1) Molecular Ecology Research Group, School of Science, Galway-Mayo Institute of Technology, Galway,

Ireland

In Ireland, mussels on exposed rocky shores constitute an interbreeding mixture of two forms of mussels, the blue mussel, Mytilus edulis, and the Mediterranean mussel, M. galloprovincialis. Results from an Irish study in the 1980s (1), using partially diagnostic allozyme markers, indicated that mussels higher up the shore were more galloprovincialis-like than those lower down. In this study we set out to test two hypotheses:

1) Recruits arriving on the shore are composed of genetically distinct cohorts that settle preferentially at different levels on the shore, and maintain genetic distinctiveness into adulthood.

2) Recruits are genetically homogeneous, but once settled they diverge genetically over time, due to within-habitat site specific-selection.

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The diagnostic Me 15/16 DNA marker was used to analyse the genetic composition of newly-settled spat recruiting to artificial substrates, which were placed at two-week intervals from May-October 2002, on the mid and low shore areas of two exposed sites in Galway Bay. Adult mussels were also collected on each sampling date. Results did not support the preferential settlement hypothesis i.e., the genetic composition of primary settlers (< 500 μm) was similar between tidal heights and shores. Neither was there evidence of post settlement selective mortality, as adults were genetically similar to settling spat. In spat and adults the frequency of the M. galloprovincialis allele was high (0.56-0.80), due to high frequencies of M. galloprovincialis (>37%) and hybrid (>33%) genotypes, and correspondingly low frequencies of the M. edulis genotype (<11%). Adult mussels from a nearby sheltered estuarine site, while significantly different to exposed shore mussels, still had low frequencies of the M. edulis genotype (<17%), indicating no apparent advantage for the genotype in this environment. There are indications that the genetic composition of mussels may be changing on the Atlantic coasts of Ireland.

(1) Gosling E and McGrath D. 1990, Marine Biology, 104: 413-418.

PRELIMINARY STUDY OF GROWTH INCREMENTS OF THE PERUVIAN

MOLLUSC SHELL TRACHYCARDIUM PROCERUM (SOWERBY, 1833) (BIVALVIA) THROUGHOUT THE LAST HALF-MILLION

YEARS

Gosselin, M.J., Fernandez, E., Guzman, N., Lazareth, C.E., and Ortlieb, L.

(1*,3,4,5) IRD, PALEOTROPIQUE, Centre IRD d'Ile de France, 32 avenue Henri Varagnat, F-93 143 Bondy

Cedex, France; (1) Marc.Gosselin@bondy.ird.fr; (2) IMARPE Instituto del Mar del Peru Esq. Gamarra y Gral Valle S/N, Chucuito, Callao - Apartado postal 22,

Lima, Peru

Through periodic biological processes of growth increments, bivalve shell carbonate structure can record daily to seasonal information on environmental variations such as food supply, water temperature or chemical composition. This sclerochronological tool can be used at high-resolution time scale on contemporary shells as environmental bioindicator or on ancient shells for paleoclimatic studies. Along the Peruvian coast, an important cause of climate variability is manifested

intensively every few years: the El Niño phenomenon (EN). During a few months positive sea surface temperature anomalies reaching several degrees severely affect the nearshore environment and local ecosystems. To investigate the occurrence and intensity of past EN events, scleroclimatological studies are developed on several species of coastal molluscs. The marine bivalve Trachycardium procerum, which is found in numerous fossil assemblages on Peru and Chile coasts, presents interesting characteristics for such studies. From Mexico (Gulf of California) to Peru (Independencia Bay) this large subtidal filtering organism, living in muddy shallow bays, is sensitive to ecological variations. Its growth rhythm is apparently well adapted to environmental changes which occur during EN events. To investigate the potential of T. procerum as a recorder of El Niño events, the structure of shells from different time periods has been studied (2005 AD, 2001 AD, 6 500 BP, 120 000 years and 400 000 years). In this preliminary sclerochronological study, we assessed 1) the shell capacity to preserve the reading of growth line patterns whatever its age, 2) the diagenetic evolution of ancient shells with the purpose of future geochemical investigations, 3) the daily growth pattern of a marked modern shell and ancient shells. Modern chemically marked shells present a mean growth of 5 µm per day during a three month period, in fall-winter austral season. Growth lines are still readable for all Quaternary shells and present different patterns according to their ages. However, some structural alterations have been noted, particularly in Pleistocene shells, partially hiding the growth increments. If T. procerum can be viewed as a reliable sclerochronological tool, changes in the mineralogical composition impose precaution on future geochemical investigations. [Contribution of the European project CENSOR (Contract N°511071).]

PERMANENT ADAPTATION AND SPECIATION

Gudimov, A.V.

Murmansk Marine Biological Institute, Murmansk, 183010, Russia; alexgud@mail.ru

Physiological, behavioral and morphological adaptations in blue mussels (Mytilus edulis L.) have been studied for several years. Adaptation is here established as a permanent process of adjustments both at the functional and structural levels (e.g. temperature/salinity tolerance and sensitivity, shape of the shell). These adjustments result in a relative increase in the capacity to survive and reproduce under changing

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conditions. Adaptations represent the principal basis for evolution. The hypothesis here is that there is no principal distinction between non-genetic and genetic adaptations. The stronger the environmental changes or differences between environmental localities and the greater non-genetic adaptations involved the more genetic changes are accumulated within each local population's group. The non-genetic adaptations comprise large-scale functional and structural changes at behavioral, physiological, (sub)cellular, tissue or organ levels as well as alterations in organismic integration. If the non-genetic adaptations are not capable to compensate adverse effects of environmental changes, such as fluctuations or new conditions, the genetic adaptations start. Their main mechanism is selection as elimination acting upon both real non-genetic (i.e. phenotypic variation) and genetic-related variation in the local population's group. Individuals of the local group with a greater fitness for continued existence (as functional and structural adjustments/adaptations) under the new conditions may enjoy advantages in survival, reproduction and competition. Finally, due to the adaptation process they are changed step by step and become different with an initial species type firstly, slightly, in some genes, and then more and more. Hence, the differences in capacity for non-genetic or genetic adaptation results in the differences of the genetic background of the local group/sub-populations involved. Under natural conditions the speciation from the selected local groups is not noticeable because of two processes, the permanent (continuous) adaptation and panmixia. Evidence for remarkable non-genetic and genetic differences between the local population's group or sub-populations is visualized only over a selection process under severe environmental changes coupled with significant isolation of the group.

TRANSGENIC EMBRYOS AND LARVAE IN MUSSELS ORIGINATED BY TRANSFECTION

OF SPERMATOZOA

Guerra Muñoz, R.L. and Esponda Fernández, P.H.

(1*) Universidad de Valparaíso. Casilla 5030, Chile; rosa.guerra@uv.cl

(2) Centro Investigaciones Biológicas (CSIC) Ramiro de Maetzu 9. Madrid-28040, Spain

Numerous reports have shown that the spermatozoon can be transfected in sea urchins (1), abalones (2), some vertebrates (3), and more scarcely bivalves (4). Our objectives were to transfect spermatozoa of Mytilus

galloprovincialis and use it for ovocyte fertilization. We employed the p-GeneGrip gene construction which encodes for the GTP (Green Fluorescent Protein) using naked DNA-Rodamine for short time of incubations.

Seventy percent of the spermatozoan nucleus appeared with the red label observed in several sections when analyzed by confocal microscopy. PCR analyses demonstrated the presence of the transgene in the DNA extracted from treated spermatozoa. Southern Blots showed that two integrations bands (7 and 10 bp) ocurred. Treated spermatozoa were employed for in vitro fertilization. The resulting embryos and larvae were analized by fluorescence microscopy for localization of GTP gene expression. A porcentage of two cell, four cell stages, morula and veliger larvae showed the green autofluorecence only in the cytoplasmatic region when they were analized in vivo. Furthemore, PCR also demonstrated the presence of the transgene in the DNA isolated from these embryos. This simple method could be a contribution for future applications in biotechnological basic pocedures for those mollusks of commercial and alimentary interest. The study was possible through grants DGM2004-0899 (España) and DIPUV 21/2003 (Chile).

(1) Arezzo F 1989, Cell Biol. Int. Rep. 13: 391-404. (2) Spadafora C 1998, BIO Essays 20: 955-964. (3) Tsai HJ et al. 1997, Transgenic Res. 6: 85-95. (4) Guerra, R et al. 2005, Cell Biol International 29:

159-164.

ABUNDANCE AS A FACTOR IN MARINE BIVALVE EXTINCTIONS OVER GEOLOGIC

TIME

Harnik, P.G. and Simpson, C.

(1*) Committee on Evolutionary Biology, The University of Chicago, 5734 S. Ellis Avenue, Chicago,

IL 60637, U.S.A.; pharnik@uchicago.edu; (2) Department of Geophysical Sciences, The University

of Chicago, 5734 S. Ellis Avenue, Chicago, IL 60637, U.S.A

Abundance is widely believed to be a primary factor in extinction and is often used to assess extinction risk in extant species. Despite our reliance on abundance in current conservation efforts, little is known about its influence on extinction dynamics over longer time scales. The bivalve fossil record can be used to test whether abundance accurately predicts extinction rates during periods of past environmental change.

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Analyses of a global dataset of marine bivalve genera from the Paleobiology Database (1), found a significant non-monotonic relationship between relative abundance and extinction rates over the last 250 million years; extinction rates decline with increasing abundance as expected, but the most abundant genera reverse from this trend (2). Further, the statistical support for the relationship between abundance and duration varies over time. This may be due to changes in the relative importance of other ecological variables, such as geographic range and body size, in survivorship. These variables have been suggested to covary with abundance in a range of organisms and have also been hypothesized to influence extinction risk. A multivariate approach is thus necessary to determine the direct and indirect influence of abundance on extinction. I am currently gathering species-level abundance, body size, and geographic range data to test a set of causal models of the interactions between these ecological attributes and their effects on bivalve extinction rates over the Paleogene (65-30 m.y.a.). These data are being compiled through a combination of field work in the south-central United States and the use of existing museum collections. Whereas the earlier analyses were conducted using global data for a diverse array of bivalve genera, this study will examine species-level evolutionary dynamics within three bivalve superfamilies (Carditoidea, Pectinoidea, and Veneroidea) from a single biogeographic province.

(1) http://pbdb.org (2) Simpson C and PG Harnik, in prep.

UNIONIFORMES: REPEATED RADIATION, CONVERGENCE, AND

PALEOBIOGEOGRAPHIC CONSIDERATIONS

Hartman, J.H., Bogan, A.E., and Bingle, M.

(1*,3) University of North Dakota, Department of Geology and Geological Engineering, 81 Cornell Stop

8358, Grand Forks, ND 58202; joseph_hartman@und.edu

(2) North Carolina State Museum of Natural Sciences, 4301 Reedy Creek Road, Raleigh, NC 27607

The existence, if not dominance, of homoplasy in shell form adaptations to certain sets of environmental parameters is generally accepted in modern Unioniformes. This condition should also hold for fossil unioniforms and represents a burden for taxonomy and global synthesis. Recognition of fossil record homoplasy is more complicated in phylogenetic analysis because of the absence of independent characters to

constrain the interpretation of convergence within potential lineages. Repeated diversifications in the Mesozoic and Cenozoic have compounded the difficulty of uniting the fossil and modern unioniform record. The perspective presented here is one of a potentially far more dynamic record of unioniform existence.

An intriguing solution to interpret interregional and long-term evolutionary relationships more precisely is to examine unioniform assemblages within a paleobiogeographic (possible paleodrainage) region. Dispersal patterns and opportunities affecting morphological convergence are thus examined in geologic context (by time interval and geotectonic setting) constraining evolutionary interpretations. Plotting modern unioniform family distributions on paleogeographic maps through discrete time intervals provides a means to assess the potential duration of a molluscan assemblage in a delimited area. In contrast, a vicariance perspective can view the development of biogeographic filters that limit potential distribution or make some fossil assignments to modern groups highly unlikely. Post-Pangaea fragmentation of continents, inundations by marine seaways, and uplifts of mountain ranges, provide filters to unioniform distribution.

Examples include the Hyriidae which are presently known from South America and Australasia. This distribution is not easily resolved, but these continents were in relatively close proximity during the Triassic. Australian fossil hyriids have been reported from each period of the Mesozoic. The separation of an effective corridor occurred in the Jurassic. Western North American interior taxodont Unioniformes, previously assigned to Iridinidae, likewise, have their last chance for African distribution (or vice versa) by the Early Jurassic. Thus an in situ radiation of unioniforms on the west side of the Western Interior Seaway near the end of the Cretaceous is a more parsimonious interpretation. These and other hypotheses are tested using existing and new fossil data and gene sequence divergence data by placing the fossil record into a time-sequenced paleobiogeographic framework.

EVOLUTION OF MOLLUSCAN ONTOGENY

Haszprunar, G.

Zoologische Staatssammlung München, Münchhausenstr. 21, D-81247 München, Germany;

haszi@zsm.mwn.de

Molluscs show an incredible diversity of all aspects of their biology and thus also of their developmental modes. Indeed, discussions on the evolution of these

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modes in general and in particular within Gastropoda and Bivalvia has been controversely subjected over two centuries. Actual debates mainly concern the mode of development (lecithotrophic versus planktotrophic), but also the original type of molluscan larva (trochophore versus pericalymma) has been disputed. During the last decade investigations by means of electron microscopy, antibody staining combined with Confocal Microscopy, and computer-aided 3D-anatomies of larval structures have been undertaken on a variety of basic molluscan representatives representing most classes: in particular general morphology, trochi, larval sensory and excretory structures, development of hard parts, myo- and neurogenesis have been comparatively investigated in Patella (Gastropoda), Mopalia (Polyplacophora), Antalis (Scaphopoda), and (partly) Chaetoderma (Caudofoveata). Although the general mode of development is identical in all these examples, there is remarkable diversity among the various larval types (trochophorae) and their detailed structures (e.g. apical organ, prototroch, protonephridia) and also myogenesis differs considerably between classes. Planktotrophic development in molluscs is restricted to Bivalvia and Gastropoda, where it can be traced also in the fossil record. In the Bivalvia, the primitive Protobranchia exclusively show lecithotrophic development. In the Gastropoda, planktotrophy is restricted to Neritaemorphi, Caenogastropoda, and Heterobranchia, whereas all basic clades (Patellogastropoda, Cocculinida, Vetigastropoda, Neomphalida) solely show lecithotrophic development. Therefore, the general phylogenetic pattern of planktotrophy provide strong evidence that a lecithotrophic mode of development via a trochophore larve is the plesiomorphic state in both cases. Accordingly, the same can be reasonably stated for the Mollusca as a whole. In addition, all available data suggest that Mollusca never was segmented. Bivalvia in particular still offers a largely unexplored field of evo-devo studies: Whereas various pteriomorph bivalves (in particular pectinids and ostreids) and certain unionidans are quite well studied by modern methodologies, data on protobranchs or heterodonts are scarce and include many significant gaps of knowledge. Main open questions and future plans of investigations will be outlined in the lecture.

KEY EVENTS IN THE EARLY MESOZOIC EVOLUTION OF BIVALVES

Hautmann, M.

University of Bristol, Department of Earth Sciences, Wills Memorial Building, Queens Road, Bristol BS8

1RJ, UK

The early Mesozoic was pivotal in the evolutionary history of bivalves, marking the beginning of a still ongoing radiation of this class. A cornerstone of the post-Palaeozoic success of bivalves was their ability to recover more quickly after the end-Permian mass extinction event than most of their competitors. In particular, pteriomorph bivalves coped much better with the reduced primary production in the wake of the extinction event than brachiopods, which was probably due to their higher filter feeding rates (1). Additionally, the long larval phase of most filter-feeding bivalves facilitated their global dispersal and thereby allowed the quick occupation of vacant niches. The recovery of bivalves peaked in the Anisian, which is reflected by a Triassic overall maximum of the origination rate. Although decreasing in the following stages, the origination rate continued to exceed the extinction rate until the Norian. New life habits evolving during that interval were related to a contemporaneous proliferation of durophagous predators and are interpreted as either passive (e.g., cementation) or active (e.g., swimming) defence strategies (2, 3). The creativity of bivalves in developing a wide range of anti-predatory adaptations was an important advantage in competition with less sophisticated prey animals such as brachiopods. Towards the end of the Triassic, the standing diversity of bivalves approached a plateau before it distinctly dropped at the Triassic-Jurassic boundary. Although less dramatic than the extinction event at the end of the Permian, some previously dominant families vanished completely (Myophoriidae) or nearly completely (Megalodontidae and Dicerocardiidae). The decline of these families is in accordance with a general suppression of taxa with thick aragonitic shells during the end-Triassic extinction event, which resulted from a temporary undersaturation of seawater with respect to CaCO3 (4). As an evolutionary response to this non-actualistic condition, several clades of bivalves replaced shell aragonite with calcite, because calcite secretion required lower metabolic costs and provided higher resistance against dissolution (5).

(1) Hautmann M & Nützel A 2005, Palaeontology 48: 1131-1138.

(2) Hautmann M 2004, Lethaia 37: 165-172. (3) Hautmann M & Golej M 2004, Journal of

Paleontology 78: 1086-1090. (4) Hautmann M 2004, Facies 50: 257-261. (5) Hautmann M in press, Facies.

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SPERMATOZOAN MORPHOLOGY OF THE ARGENTINEAN SURF CLAM DONAX

HANLEYANUS (BIVALVIA: DONACIDAE)

Herrmann, M., Giménez, J., Laudien, J., and Penchaszadeh, P.E.

(1*, 3) Alfred Wegener Institute for Polar and Marine research (AWI) Bremerhaven, Germany; (1)

mherrmann@awi-bremerhaven.de (2, 4) Lab. Invertebrados, DBBE, Facultad de Ciencias

Exactas y Naturales, Universidad de Buenos Aires (UBA), Argentina

Ultrastructural descriptions of spermatozoa are a useful tool to reveal bivalve phylogeny. Several Donax species living off Latin America show strong morphological variability that often generates discussion on the validity of the species identity. This study is the first attempt to describe the structure of spermatozoa of Donacidae from the southwestern Atlantic Ocean. Donax hanleyanus (Philippi, 1842) is a free-spawning marine bivalve inhabiting exposed intertidal sandy beaches and has a geographic distribution along the Atlantic coast of South America, from Rio de Janeiro, Brazil (22°51'S) to Mar del Plata, Argentina (38°20'S).

Transmission electronic microscope (TEM) and scanning electron microscopy (SEM) confirmed that euspermatozoa of D. hanleyanus can be classified as "aquasperm type" common for many bivalves. The head is composed of an spheroidal nucleus capped by a conical acrosome vesicle showing an anterior extension (total length 2 µm). The mid-piece region consists of an axoneme with a short basal fossa containing the centriolar complex and an initial portion of a 9+2 axoneme, sheathed by 4-5 spherical mitochondria. The single flagellum shows the typical 9+2 microtubule structure. Specifications useful for taxonomy are highlighted.

APPLICABILITY OF THREE FLUORESCENT MARKERS FOR GROWTH ESTIMATIONS OF

THE SURF CLAM DONAX HANLEYANUS

Herrmann, M., Laudien, J., Arntz, W., and Penchaszadeh, P.E.

(1*, 2, 3) Alfred Wegener Institute for Polar and Marine Research (AWI), Bremerhaven, Germany;

(1*)mherrmann@awi-bremerhaven.de (4) Lab. Invertebrados, Depto. Biología, Facultad de

Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), Argentina

A non-lethal method providing growth tags is a precondition for many in-vivo experiments investigating growth of marine invertebrates. This study determines the effectiveness of Calcein, Alizarin Red and Strontium chloride hexahydrate in marking Argentinean surf clams (Donax hanleyanus) under controlled conditions. Wild specimens, collected from Faro Querandi (Buenos Aires province, Argentina), were taged using different concentrations of each stain and several immersion periods. After marking, animals were reared in an aquaculture system to allow growth. Mortality, body condition and growth rate were measured for 20 days to assess the effects of the treatments. To detect the incorporated marks, shells were cut and sections analyzed using scanning electron microscopy for Strontium chloride hexahydrate and fluorescence microscopy for Calcein and Alizarin Red.

Results demonstrate that Calcein was the best growth marker as it provides a long-lasting, readily detected fluorescent mark that can be used to measure shell growth accurately, even at low concentrations and immersion periods. In addition, marking with Calcein did not affect survivorship or growth and thus is considered to be the best stain evaluated for Donax hanleyanus.

BIOMETRICAL AND HIGH RESOLUTION TRACE ELEMENT (MG, SR AND NA)

STUDIES IN CRASSOSTREA GIGAS SHELLS OF THREE ESTUARIES OF CANTABRIA (SPAIN): SEASONAL, ANTHROPOGENIC

AND ONTOGENETIC INFLUENCES

Higuera-Ruiz, R. and Elorza, J.

Depto. Mineralogía y Petrología. Universidad del País Vasco, Apdo. 644; 48080 Bilbao, Spain; (1*)

npbhirur@lg.ehu.es

Living Crassostrea gigas oysters of different ages and sizes have been collected in three estuarine zones of Cantabria (Spain): a) San Vicente de la Barquera Estuary (SVE), ten oysters of known age, 2 years old and similar size; b) Santander Bay (SB), ten oysters of unknown age, and c) Marismas de Santoña Estuary (MSE), ten oysters of unknown age. A shell biometrical study, with the aid of three indexes, shell thickness index (STI) (1) and weight and volume indexes, indicates that the oysters of SB have developed shell

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anomalies, like abnormal thickening and loss in vital cavity volume, due to the chronic exposition to tributyltin (TBT), a toxic chemical agent used in antifouling paints, which utilization has been banned for vessels less than 25 m. In the other two estuaries the oysters have not shown that type of anomalies. Three high resolution trace element, Mg, Sr, Na, geochemical transects, one analysis every 15 microns, with a total of 1558 points, determined by Electron Probe Microanalysis (EPMA), and realized following an sclerochronological profile, has been carried out on thin sections of the microstructures presented in the chondrophore area of a representative oyster of each estuarine zone. The microstructures analyzed, regular foliated (RF) and Complex Cross Foliated (CCF) have been determined with the aid of a Scanning Electron Microscope (SEM). The analyzed trace elements exhibit cyclic variations in SVE and MSE, related with seasonal and ontogenetic periods, and characterised by broad maxima during spring and early summer, but not in SB. The existence of marine pollution in SB may have produced a minor abnormal incorporation of some elements, like Mg, in the skeletal hard parts. In the RF of MSE are also well visible tidal growth lines with switching zones, characteristic of an exposure to semidiurnal tidal cycles (2). This study highlights the potential of Crassostrea gigas shell as sentinel species and environmental recorder.

(1) Alzieu C. 1982, Revue des Travaux de L´institut des Pêches Maritimes, 45: 101-116.

(2) Ohno T. 1989, Palaeontology, 32: 237-263.

GEOMETRIC MORPHOMETRICS OF CONVERGENT SPECIES PAIRS OF THE

SUBFAMILIES VENERINAE AND CHIONINAE

Kappner, I.

Field Museum of Natural History, Department of Zoology, Division of Invertebrates, 1400 S. Lake Shore

Drive, Chicago, IL 60605, USA; ikappner@fieldmuseum.org

The taxonomy of the economically important marine bivalve subfamilies Venerinae and Chioninae has been matter of debate for over a century. Recently our molecular phylogeny (1) on these two groups showed that these subfamilies are clearly distinct. However, our study also showed that the longstanding taxonomic confusion was understandable given the available conchological data. Indeed, several species pairs that had been thought to be closely related due to their

overall similarity of shell morphology are in fact genetically distinct from each other and should be assigned to separate subfamilies. This indicates a high level of homoplasy in the morphological shell features. Consequently, systematics based only on traditional shell characters is misleading for these groups. In some cases the morphological similarity of these species pairs from different subfamilies is quite remarkable. Any remaining divergence in shell shape of those two groups could therefore represent basic features which are more resistant to evolutionary change. For example, internal organs could constrain the evolutionary convergence of shell anatomy. In order to identify any underlying differences, I employed geometric morphometrics in the present study to quantify the shape of the species pairs in population samples. I digitized landmarks of easily recognizable internal conchological features and used vector deformation to reveal regions of greatest change. For the species pair /Clausinella punctigera/ and /Lirophora paphia/ the biggest differences are found in the region of the pallial sinus and between the adductor muscle scars. There is no species overlap in this pattern of distribution and thus these features can reliably discriminate the two taxa. To simplify this difference for identification purposes, I investigated whether simply measuring an angle (between the pallial sinus, hinge and adductor muscle) gives an equally robust discrimination. The angle proved to be reliable and thus geometric morphometrics may be generally useful to identify new characters based on the inter-relationship of shell features. I will discuss how the post-Eocene radiation of the Chioninae and Venerinae may have created the conditions for the convergences of shell shape to arise.

(1) Kappner I and Bieler R in press, Molecular Phylogenetics and Evolution, doi:10.1016/j.ympev.2006.02.006

PHYLOGENETIC STUDIES OF THE MARINE BIVALVE SUBFAMILY VENERINAE

Kappner, I. and Bieler, R.

(1*, 2) Field Museum of Natural History, Department of Zoology, Division of Invertebrates, 1400 S. Lake Shore

Drive, Chicago, IL 60605, USA; (1) Department of Biological Sciences, University of Ilinois at Chicago;

ikappner@fieldmuseum.org

Venerinae (Heterodonta: Veneridae) is a diverse, commercially important, and cosmopolitan marine bivalve subfamily. Recent workers synonymized it with the subfamily Chioninae, due to its overall morphological similarity. The use of traditional shell-

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based characters alone, however, is questionable for resolving phylogenetic relationships of this group. A phylogenetic study was carried out, based on nucleotide sequences of the mitochondrial large subunit (16S), cytochrome oxidase subunit I (COI), and the nuclear protein-coding gene histone 3, to investigate the relationships and circumscription of Venerinae and the phylogenetic pattern of characters in this group. This study consists of a total of 55 taxa: 13 venerine genera, 24 chionine taxa, and 18 taxa of other venerid subfamilies. We analyzed the alignments using a Bayesian approach using Markov Chain Monte Carlo (B/MCMC) tree sampling and maximum parsimony methods.

The resulting phylogenetic hypothesis suggests that Chioninae and Venerinae are actually discrete taxa, but that the circumscription suffered from misplacement of some genera. Our analysis showed that the former chionine genera Chamelea and Clausinella should be placed in Venerinae, as sister taxa to Venus, and that the former Chioninae taxa Tawera and Timoclea are basal within the Venerinae. We re-analyzed morphological and anatomical features in light of the molecular data to describe monophyletic entities. Features of the hinge and internal shell as well as the degree of siphonal fusion are identified as characters to morphologically distinguish the two subfamilies. Of the three genes used in this study, only COI (commonly used as "barcoding" gene) posed substantial problems in obtaining sequence data from older museum material.

EVALUATION OF SPONDYLUS GAEDEROPUS LINNÉ, 1758, MASS

MORTALITY EVENT IN THE COLUMBRETES ISLANDS MARINE

RESERVE (WESTERN MEDITERRANEAN, SPAIN)

Kersting, D.K., García-March, J.R., and Templado, J.

(1*) Columbretes Islands Marine Reserve. SGPM-Tragsa. C/ Músico Perfecto Artola, 6A, 12003 Castelló,

Spain; dkerstin@tragsa.es (2) Marine Biology Laboratory, University of Valencia. C/ Dr. Moliner, 50, 46100 Burjassot (Valencia), Spain;

jose.r.garcia-march@uv.es (3) Museo Nacional de Ciencias Naturales, C/ José

Gutiérrez Abascal, 2, 28006 Madrid, Spain

Columbretes is a group of small volcanic islands located 30 nautical miles off the coast of Castelló (Spain) on the Balearic basin at the Mediterranean Sea. The

Columbretes Islands Marine Reserve was created in 1990 by the Spanish Fishing Authority, Secretaría General de Pesca Marítima, Ministerio de Agricultura Pesca y Alimentación, and since then has become one of the best preserved marine environments on the western Mediterranean. A mass mortality episode affecting the bivalve Spondylus gaederopus was detected during the summer of 2005. Mortality was also observed, although to a lesser degree, on the arcoid bivalves Barabatia barbata and Arca noae. In order to evaluate the mortality of Spondylus, its distribution was censed on known surface areas in L'Illa Grossa inlet.

A total surface of 401.9 m² was surveyed and 720 S. gaederopus specimens counted. The average density was 2.3 ± 1.6 SD specimens/m² and maximum density reached 6.8 specimens/m² (n=27 areas). The total mortality rate reached 99.3 %. The origin of this massive mortality is still unknown. Seawater temperature does not seem to be the cause, as there was no temperature anomaly during the summer of 2005. Similar mortality events were detected in the northwestern Mediterranean during the summer of 1981, 1982, and 1983 (1), and the authors suspected either bacterial, fungal or viral infection as the main mortality cause.

(1) Meinesz & Mercier, 1983. Trav. sci. Parc nation. Port-Cros 9: 89-95

THE MITOCHONDRIAL GENOMES OF THREE EUROPEAN LIMIDAE. HIGH

REARRANGEMENT RATES ON GENUS LEVEL AND INTRASPECIFIC DIFFERENCES

Knapp, M., Dreyer, H., and Steiner, G.

(1, 2, 3) Molecular Phylogenetics, Department of Evolutionary Biology, University of Vienna, Althanstr.

14, A-1090 Vienna, Austria; (1*) Limaria@gmx.at

The mitochondrial genomes of Mollusca, and those of Bivalvia in particular, show a high variability in gene order. Only among closely related species such as Mytilus trossulus, M. edulis and M. galloprovincialis gene order is conserved. We compare the near complete mt-genomes of three limid species belonging to two genera: Limaria hians, L. inflata and Acesta excavata.

All three mt-genomes are about 16 kb in length, they contain the usual genes except for the Atpase subunit 8, all encoded on the same strand as in all other published marine bivalve mt-genomes. The gene order of the two Limaria species differs by two major gene rearrangements: cox3+nadh3 changed place with

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rrnS+rrnL and nadh5 changed place with the large gene block including the genes for nadh4l, cytb, nadh6, a putative control region, cox1 and eight tRNA-genes. Compared to the mt-genome of the polyplacophoran Katharina tunicata, representing the plesiomorphic mitochondrial gene order in Mollusca, at least six breakpoints are required between the major genes. The gene order of Acesta excavata has little in common with the other two limids or Katharina. The only conserved gene junction is tRNA Leu (uag) + nadh1, found in most metazoan; Limaria inflata and Acesta share the junction rrnL + cox2. Limaria hians shows intraspecific variation in nucleotide and aminoacid sequences and in a putative tRNA structure. The tRNA-like sequence at the 5' -end of cox3 differs in all individuals. A putative control region between rrnL and cox3 with tandem repeats is not present in female specimens resembling the 'Mytilus - situation' (1). Although we suspect separate female and male mt-genomes (doubly uniparental inheritance - DUI), further studies on more individuals are required to confirm this (for detailed figures and explanations see Poster!). This is an example that bivalve gene order may vary among closly related species and that duplication and random loss of genes play an important role in genome rearrangements. Our data dampens the hope to resolve the phylogeny of Bivalvia using mt-gene order. However it has a great potential for questions at lower taxonomic levels.

(1) Mizi A et al. 2005, Mol Biol Evol. 22(4): 952-67.

HIGH-DIVERSITY BIVALVE FAUNAS IN THE MIDDLE JURASSIC OF THE

SOUTHERN BALTIC SEA

Koppka, J., Hinz-Schallreuter, I., and Fürsich, F.T.

(1*,2) Ernst-Moritz-Arndt-University, Institute of Geography und Geology, Dpt. of Palaeontology and Historical Geology, Friedrich-Ludwig-Jahn-Str. 17a,

D-17489 Greifswald, Germany (3) Institute of Palaontology, Julius-Maximilians-University, Pleicherwall 1, D-97070 Würzburg,

Germany

In the southern Baltic region, highly fossiliferous, shallow marine Middle Jurassic strata are widely distributed but mostly covered by Cretaceous to Quaternary deposits or underneath the Baltic Sea. Good exposures, which occur only in Lithuania, and borehole material and glacial erratic boulders in NW-Poland (Pommerania) and NE-Germany (Vorpommern) have been intensively studied for the bivalve content. Erratic boulders are of particular interest for their abundance in

Quaternary deposits and their numerous and extraordinarily preserved bivalves and other molluscs. The lower Bajocian to Callovian sediments belong to a variety of lithotypes (e.g. ferrugineous calcareous sandstones, iron oolites, marly limestone nodules) among which aragonite and colour preservation is not uncommon. Their excellent preservation permits detailed studies of taxonomically important hinge and shell structures, micro-relieves on shell surfaces and ontogenetic investigations (the latter on isolated material from weathered glacial erratic boulders and borehole samples).

Until now, more than 160 species representing ca. 67 genera have been identified, many more than previously known. In Pommerania, the diversity peak falls within the jason (ammonite) Zone of the Middle Callovian and in Lithuania within the upper coronatum (ammonite) Zone. With 19 respectively 11 genera, Heterodonta and Anomalodesmata represent the largest groups. Heterodonta are shallow-burrowing infaunal suspension-feeders among which Nicaniella, Pressastarte, Tancredia, Protocardia, Anisocardia and Isocyprina predominate. Deep-burrowing suspension-feeding anomalodesmatans, mainly belonging to Pleuromya, Goniomya, Pholadomya, are restricted to more stable, only storm-affected clayey sands. Deposit-feeding nuculoids such as Palaeonucula, Nuculoma, Mesosacella are typical in clay sediments but also occur in the intercalated sand layers and limestone nodules. High-energy environments with repeated reworking of the sediments are generally characterized by small or juvenile specimens and a high rate of fragmented shells. Heterodonta prevail in this type of environment while Anomalodesmata are extremely rare or lacking. Epifaunal oysters and pectinids prefer more stable conditions and are thus more frequently observed together with Anomalodesmata. The respective environment yields the highest bivalve diversity with 70 species known from Pommerania and 40 from Lithuania.

INTERACTIVE EFFECTS OF TEMPERATURE, SALINITY AND FOOD

AVAILABILITY ON THE SHELL FORMATION OF MYTILUS EDULIS

Kossak, U. and Wahl, M.

IfM-GEOMAR Leibniz Institute of Marine Sciences Düsternbrooker Weg 20, D- 24105 Kiel, Germany; (1*)

ukossak@ifm-geomar.de

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Climate change models for the coming 50 years predict warming, salinity shifts and altered nutrient regimes for the Baltic Sea (1, 2, 3), which can be expected to affect the ecosystem and its inhabitants in various ways. Due to its high abundance and trophic key role, the blue mussel Mytilus edulis is considered one of the key players in the Baltic ecosystem (4). Any change in its life history and ecological performance may have far-reaching consequences. Features that most probably are affected by the predicted environmental changes, in particular by salinity reduction, are growth and shell stability (5). Such changes may not be trivial since faster growth will lead to larger mussels in less time and thus to higher overall filtration and earlier escape from predation by crabs. Weaker shells will keep the mussels for a longer time within the predation spectrum of crabs and reduce reproduction and population growth. In a 3-factorial laboratory experiment we tested how salinity, temperature and food availability affect mussel shell growth and shell stability, with a special focus on the interactions among the tested factors.

We found significant impacts on growth rates of all 3 factors, and significant effects of salinity and temperature on shell stability. The interactions among factors were significant as well. For 'ground-truthing' of the salinity effect, a multiple transplant experiment was run in the field. The translocation to another salinity-region simulated the predicted changes in salinity. Mussels from populations along the Baltic salinity gradient were exchanged reciprocally between 6 stations. We assessed how mussel populations from different salinity regimes in the Baltic performed in new salinity conditions. After 3 months at the destiny site, growth rates, shell thickness and shell stability were measured. It turned out that growth rates of all mussels, regardless of their origin, were highest at the station with a salinity of 24 psu. Our results indicate that while single mussel properties are influenced by single climate change parameters in predictable ways, the simultaneous change of more than one climate parameter may produce unexpected effects. This underlines the importance of considering multi-factor interactions when studying global change impacts.

(1) Beniston M et al. 1998 Intergovernmental Panel on Climate Change, Cambridge University Press, pp. 149 - 185.

(2) Graham P 2004, Ambio, 33: 235-241. (3) Omsted A et al. 2000, Climate Research, 15, 95-

108. (4) Kautsky N 1982, Marine Biology, 68: 117-133.

(5) Tedengren M 1990, Marine Ecology Progress Series, 59: 221-227.

FATTY ACID COMPOSITIONS OF CARDIOLIPIN IN MARINE MOLLUSK

BIVALVES - PHYLOGENETIC OCCURRENCE AND FUNCTIONNAL

SIGNIFICANCE

Kraffe, E., Grall, J., Leduff, M., Guderley, H., and Marty, Y.

(1*, 5) UMR CNRS 6521, Université de Bretagne Occidentale, CS93837, 29238 Brest, France; (1*)

Edouard.Kraffe@univ-brest.fr; (2, 3) UMR CNRS 6539, Institut Universitaire Européen

de la Mer, 29280, Plouzané, France; (4) Département de Biologie, Université Laval, Québec,

Canada

The fatty acid (FA) composition of a peculiar phospholipid class, the cardiolipin (CL), was described in 45 different species of marine bivalve molluscs. All the CL compositions could be grouped according to only three characteristic FA profiles. The "type 1" was characterized by a very high level of 22:6(n-3) (> 80%), the "type 2" by the presence of 22:6(n-3) jointly with 20:5(n-3) and the "type 3" by 22:6(n-3) jointly with 18:2(n-6) and 18:3(n-3). These different profiles were not found to be linked with the phytoplanctonic diet of bivalves, but appeared to be correlated with bivalve phylogeny (1). Indeed, all "type 1" CL species belong to the Eupteriomorphia (Filibranchia) and all "type 3" CL to the Pteriomorphia (Filibranchia) groups, while those having "type 2" CL were members of the Heterodonta group (Eulamellibranchia). The only analyzed freshwater bivalve species (Anodonta imbecilis) showed a distinct FA composition that would confirm the monophyly of Paleoheterodonta (1). Thus, these typical FA compositions are likely to be genetically controlled and could be involved in CL functions. The CL class is specifically located in the inner mitochondrial membrane, and is a key factor in the control of major proteins implicated in oxidative phosphorylation (2). In mammals, 18:2(n-6) is typically associated with CL (> 80%) (2), and an incorporation of 22:6(n-3) could influence oxidative phosphorylation (reduction of O2 consumption - increase of ATP production) (3).

In marine bivalves we presumed that, relatively to Eupteriomorphia, the presence of 20:5(n-3) in Heterondonta reflects a specific adaptation of the mitochondrial respiratory processes during bivalve evolution. To go into this hypothesis, mitochondria were purified from an eulamellibranch (Mya arenaria) and a filibranch (Crassostrea gigas) bivalve, and the activity of respiratory chain complexes were measured. We showed that FA compositions of CL could be

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implicated, at least in part, in the different activities found for specific complexes (I, III and IV) that could contribute to differences in tissue aerobic capacity between Eulamellibranchia and Filibranchia.

(1) Giribet G and WC Wheeler, Invertebrate biology 121: 271-324.

(2) Schlame M et al., 2000, Prog. Lipid Res. 39: 257-288.

(3) Yamaoka S et al., 1988, J. Nutr. 118: 290-296.

DIVERSITY OF THE PLIO-PLEISTOCENE MEDITERRANEAN BIVALVIA: STATUS OF

KNOWLEDGE AND PROSPECTS

La Perna, R.

Dipartimento di Geologia e Geofisica, Università di Bari, Via Orbona 4, 70125 Bari, Italy;

r.laperna@geo.uniba.it

During the last two centuries a huge amount of literature on the Mediterranean Plio-Pleistocene molluscs has been produced. However, such a great amount of data can be managed with difficulty because of the great systematic confusion reigning over this knowledge and to the scarcity of modern revisions. Bivalves are probably better known, thanks to their comparatively lower diversity and smaller taxonomic complexity. The recent literature (1) documents a dramatic drop in the diversity of Mediterranean shallow water bivalves at about 3.0 My, followed by minor events of extinction-disappearance, all approximating major climatic changes. According to these data, the Middle-Late Pliocene and Pleistocene bivalve fauna was markedly poorer than the Early Pliocene one, but this strikingly contrasts with the unusually rich modern fauna from the Mediterranean. However, a recent revision of the shallow water Pleistocene Nuculidae pointed out an unexpectedly higher diversity (9 species vs. 4-5 as currently known), suggesting that the diversity of the Pleistocene shallow water fauna has been roughly underestimated. Recent works, mostly focusing on the protobranch bivalves (2, 3), have outlined important changes in composition and diversity also within the bathyal fauna during the Plio-Pleistocene. Its history appears totally different from that of the shallow water counterpart, with an increasing diversity since the Middle Pliocene and a dramatic drop in the Late Pleistocene. Most attention has been paid to extinction of warm water species in the Pliocene and immigration of Boreal Guests in the Pleistocene, as main aspects of changes in diversity. However, much work should be done to know better what happened in the

Mediterranean during the last few million years in terms of diversity and how much important was the contribution of climatic and oceanographic changes in promoting differentiation and appearance of new species within the shallow and deep water fauna. To do this, there is a strong need to leave old views based on "tradition" and to apply a strictly systematic treatment.

(1) Monegatti P & Raffi S 2001, Palaeogeogr. Palaeoclim. Palaeoecol. 165: 171-193.

(2) La Perna R 2003, Boll. Malacol. 39: 17-34. (3) La Perna R 2004, J. Nat. Hist. 38: 1045-1057.

A COMPREHENSIVE PHYLOGENY OF THE HOLARTIC SPHAERIINAE (VENEROIDA,

SPHAERIIDAE): SYSTEMATICS AND GENOME AMPLIFICATION

Lee, T.

Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann

Arbor, MI 48109, USA; taehwanl@umich.edu

The Sphaeriidae (fingernail/pill/pea clams) are ubiquitous in freshwater ecosystems and represent one of the three major molluscan radiations into freshwater habitats (1). They first appear in the Cretaceous fossil record (2), and morphological (3) and molecular (4) phylogenetic studies distinguish two primary clades: the cosmopolitan Sphaeriinae, which have maximum diversities in the Holarctic Region, and the Gondwanan Euperinae. Sphaeriinid systematics has historically been hampered by considerable ecophenotypic and allometric variation in shell shape (5) and the relative dearth of informative morphological synapomorphies (6) - limitations now largely overcome by molecular phylogenies (4). Sphaeriinids exhibit a remarkable degree of genome amplification (2n=30-247) (7) and a number of North American species may share ancestral genome duplication events that predate their cladogenesis (8). The recent karyological discoveries have added another dimension to the speculation about evolution of genome duplication in the subfamily. A diploid North American species, Sphaerium rhomboideum (2n=44), was identified for the fist time and two diploid cyto-types (2n=30 or 36) have been found from European S. corneum. These results indicate that a very significant variation not only in ploidy levels (2n-13n) but diploid numbers (30-44) occur in the Sphaeriinae.

(1) Kuiper JGJ 1983, Basteria, 47: 3-52.

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(2) Keen M & Casey H 1969, In: Moore RC (ed.), Treatise on invertebrate paleontology. Pt. N, Vol. 2, Mollusca 6. Bivalvia. Geological Society of America and University of Kansas Press, Lawrence, Kansas, pp. N664-N669.

(3) Korniushin AV & Glaubrecht M 2002, Zoologica Scripta 31:415-459.

(4) Lee T & ´O Foighil D 2003, Zoological Journal of the Linnean Society 137: 245-260.

(5) Dyduch-Falniowska A 1983, Acta Zoologica Cracoviensia, 26: 251-296.

(6) Lee T 2004, American Malacological Bulletin, 19: 1-13.

(7) Lee T 1999, Cytologia, 64: 247-252. (8) Lee T & ´O Foighil D 2002, Molecular

Phylogenetics and Evolution, 25:112-124.

PLACING THE FLORIDIAN MARINE GENETIC DISJUNCTION INTO A REGIONAL

EVOLUTIONARY CONTEXT USING THE BRACHIDONTES EXUSTUS SPECIES

COMPLEX

Lee, T. and Ó Foighil, D.

Museum of Zoology, The University of Michigan, Ann Arbor, MI 48198-1079, U.S.A. (1) taehwanl@umich.edu

The well-documented Floridian "Gulf/Atlantic" marine genetic disjunction provides an influential example of presumed vicariant cladogenesis along a continental coastline for major elements of a diverse nearshore fauna. However, it is unclear if it represents a local anomaly for regionally distributed morphospecies, or if it is merely one of many such cryptic phylogenetic splits that underlay their assumed genetic cohesiveness. We aimed to place the previously characterized scorched mussel Gulf/Atlantic genetic disjunction into a regional phylogenetic perspective by incorporating genotypes of nominal conspecifics sampled throughout the Caribbean Basin as well as those of eastern Pacific potential geminate species. Our results show it to be one of multiple latent regional genetic disjunctions, involving five cryptic Caribbean species, that appear to be the product of a long history of regional cladogenesis. Disjunctions involving three stem lineages clearly predate formation of the Isthmus of Panama and of the Caribbean Sea, however four of the five cryptic species have within-Basin sister relationships. Surprisingly, the Atlantic clade was also found to be widespread in the southern Caribbean and ancestral demography calculations through time for Atlantic coast-specific genotypes are consistent with a northward range

extension after the last glacial maximum. Our new data seriously undermine the hypothesis of a Floridian vicariant genesis and imply that the scorched mussel Gulf/Atlantic disjunction represents a case of geographic and temporal pseudocongruence. All five Caribbean Basin cryptic species exhibited an intriguing pattern of predominantly allopatric distribution characterized by distinct geographic areas of ecological dominance, often adjoining those of sister taxa. This pattern of distribution is consistent with allopatric speciation origins, coupled with restricted post-speciation range extensions. A number of lines of indirect evidence favor the hypothesis that the predominantly allopatric distributions are maintained, over evolutionary timescales, primarily by post-recruitment ecological filters rather than by oceanographic barriers to larval-mediated gene flow.

INCIDENCE OF POLYDORA SP. ON THE MANGROVE OYSTER CRASSOSTREA

RHIZHOPHORAE (GUILDING, 1828) FROM TWO COASTAL LAGOONS OF MARGARITA

ISLAND, VENEZUELA

Liñero-Arana, I., Delgado-Blas, V.H., Díaz-Díaz, O., and Magan, I.

Infestation of bivalve molluscs of commercial importance, by spionid polychaetes (e.g., Polydora, Dipolydora, Carazziella) has been recorded on many occasions (1). These organisms excavate burrows in the shell affecting the growth of the host bivalve and increasing its mortality, mainly by weakening the shell and making them more susceptible to diseases. We have studied the infestation of the mangrove oyster Crassostrea rhizophorae by the spionid polychaete Polydora sp. During monthly collects (January-August 2002), the oysters were separated from mangrove roots growing in La Restinga (11º00´00"N, 64º10´00"W) and Las Marites (10º53'00''N, 63º53'54''W) coastal lagoons. The presence or absence of the polychaetes, the intensity of the attack was recorded in both valves of each specimen in order to establish the infestation level (2).

One hundred seventy-five bivalves, from La Restinga, were examined, verifying that 64.57% of these were infected by Polydora sp. 13.71% showed a high infestation level and 66.67% of them had commercial size (60-90mm). Differences between the monthly biomass of the compartments and number of galleries were not significant. But highly significant differences were found in the abundance of galleries in right and left valves (Ts=5,786 ***, p 0.001), being the right

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valve more infected. In Las Marites lagoon, 260 bivalves were examined and only four oysters were infested, representing a 2% of incidence. Apparently the infestation level depends on environmental conditions such as temperature, intertidal levels, oyster density and salinity (3). In the present survey, salinity is the only parameter that can be related to the low incidence of infestation in oysters from the Las Marites, whose salinity values ranged between 30 and 31 psu whereas in La Restinga these values ranged from 38 to 45 psu. This is the first study related to the incidence of Polydora sp. on C. rhizophorae from the northeastern coast of Venezuela.

(1) Basilio CD, Cañete JI and Rozbaczylo N 1995. Rev. Biol. Mar. Valparaíso 30 (1): 71-77.

(2) Ciocco NF 1990. Biol. Pesq. 19: 9-18. (3) Handley S and Bergquist P 1997. Aquaculture 153:

191-205.

NEW MICROSATELLITE MARKERS FOR THE ECOSYSTEM ENGINEER PERUMYTILUS PURPURATUS

Llavona, A., Presa, P., Guiñez, R., Astorga, M., Toro, J., and Pérez, M.

(1, 2, 6) University of Vigo, Faculty of Biology, Department of Biochemistry, Genetics and Immunology,

36310 Vigo, Spain; (3) Universidad de Antofagasta, Facultad de Recursos del Mar, Instituto de Investigaciones Oceanológicas,

02800 Antofagasta, Chile; (4) Universidad Austral, Instituto de Biología Marina

Dr. Jürgen Winter, 567 Valdivia, Chile; (5) Universidad Austral, Facultad de Pesquerias y

Oceanografia, Instituto de Acuicultura, 1327 Puerto Montt, Chile.

The ecological dominance by filtering invertebrates is a typical feature of the Chilean intertidal rocky shore (1). The "chorito maico" Perumytilus purpuratus is a dominant species of the primary space and an ecosystem engineer. Its distribution and morphometric properties (shape, width and asymmetry of valves) have been intensively described along 3,900 km of Chilean coast, from Arica (18ºS) to Tierra de Fuego (53ºS), with a special emphasis put on the Antofagasta Bay (2). Both, the ecological and adaptive meanings of such distributional and morphological traits are being currently investigated from ecological and genetic perspectives, through an interdisciplinary cooperation between Chilean and Spanish scientists (3). A compulsory tool for the fine genetic analysis at

intraspecific scale, is a highly polymorphic genetic marker. Such a marker should not only be useful to inform us about the regional diversity of populations but also about dispersive patterns, reproductive systems, and individual gametic contributions. In this study we have standardised eight microsatellite loci from the genome of P. purpuratus, the technical development and final achievements of which are briefly presented here.

Five hundred and forty five recombinant clones were picked up from culture plates and grown up to amount enough material for southern transfer. Seventy clones (13%) showed a positive signal after filter hybridisation with synthetic oligonucleotide probes ((AC)13, (GATA)7, and (GACA)7)), and were subsequently sequenced. Forty two clones (60%) out of 70 did not contain microsatellite-like regions, six remained unsequenceable and 19 clones (27%) had at least one repeated motif. Eight (42%) out of 19 microsatellite-containing sequences did not allow for primer design, and 3 sequences were redundant (16%). The remaining 8 sequences (42% of all microsatellites; 11% of the observed positives in southern, and 1.5% of the initial plated cultures) allowed for primer design and further analysis of polymorphisms using PCR and acrylamide electrophoresis. These new markers can be used as a powerful intraspecific genetic tool to undertake fine population and individual studies in P. purpuratus and to provide insights into the dynamics and significance of regional polymorphisms. [Funded by projects FONDECYT (Chile) #1050848 y # 7050074, sponsored by Hucoa-Erloss (Spain).]

(1) Prado L et al. 2006, J. Marine Biological Association UK 86:417-421.

(2) Guiñez R et al. 1999, American Naturalist 154: 341-357.

(3) Guiñez R et al. 2005, Oikos 110 : 186-190.

FIRST EVIDENCES OF A MAJOR RADIAL FOLD IN THE INOCERAMID (BIVALVIA)

SHELL

López, G.

Dep. Geologia (Paleontologia), Fac. de Ciències. Universitat Autònoma de Barcelona. E-08193

Bellaterra (Spain); gregori.lopez@uab.es

Inoceramids are an extinct group of pterioid bivalves whose rather high speciation rate and almost cosmopolitan distribution makes them biostratigraphically important especially for the Cretaceous period. However, the use of inconsistent

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taxonomic criteria and resulting controversies require a new taxonomical classification. One of the major subsisting problems concerns the origin of a major radial "sulcus" in the inner natural cast and following the growth axis of many specimens. The presence of this "sulcus" has lead Whitfield (1) to erect the genus Endocostea, literally defining it by the presence of an "oblique internal rib", and since then numerous species have been assigned to this genus. However, in the past 30 years it became increasingly clear that the internal sulcus also appears in species of other genera. Some scientists therefore hypothesised that the sulcus was caused by a parasite.

A recent study of thousands of sulcate internal casts of inoceramids from Europe and Africa sheds new light on this issue. Hundreds of "bivalved" casts from Spain, Calabar (Nigeria) and the Gosau (Austria) reveal that a sulcus is present in both valves. Although the ontogenetic onset varies in different specimens, it does start at the same growth stage in the opposed valves of a specimen; this observation contradicts quite convincingly the parasite hypothesis. Furthermore, two exceptional specimens from the Gosau (Austria) housed at the Natural History Museum in Vienna (Austria), in which the sulcus begins close to the umbo, show that the well-adapted shell does not increase in thickness. The sulcus therefore represents a shell fold - and not an internal rib as was originally assumed. In addition, its occurrence in various genera suggests that it is an environmentally induced and thus non-inheritable trait; this would be comparable to the shell geniculations developed in species with or without this major radial fold. Consequently, the genus Endocostea is insufficiently defined and most probably invalid. This interpretation has significant consequences for a revision of the inoceramid classification.

(1) Whitfield, K.P. 1880. In: Newton H. and Jenney W.P. Report on the geology and resources of the Black Hills of Dakota. U.S. geographic and geologic Survey, Rocky Mountains Region: 329-470.

INOCERAMID'S (BIVALVIA) GEOCHEMICAL SIGNAL: A DIAGENETIC

AND PALAEOENVIRONMENTAL TOOL

López, G., Gómez-Alday, J.J., Jiménez-Berrocoso, A., and Elorza, J.

(1) Dep. Geologia (Paleontologia), Fac. de Ciències. Universitat Autònoma de Barcelona, E-08193

Bellaterra (Spain); gregori.lopez@uab.es (2) Grupo de Teledetección y SIG. Instituto de

Desarrollo Regional. Universidad de Castilla-La Mancha (UCLM), Campus Universitario de Albacete,

s/n, E-02071 Albacete, Spain; JuanJose.Gomez@uclm.es

(3) Dept. of Geological Sciences (University of Missouri), 101 Geological Sciences Building, Columbia,

MO, 65211, USA; jimeneza@missouri.edu (4) Dep. de Mineralogía y Petrología. Universidad del

País Vasco, Apartado 644, 48080 Bilbao, Spain; nppelzaj@lg.ehu.es

Inoceramid bivalves are reputed Cretaceous biostratigraphical tools, provided their cosmopolitan distribution and short stratigraphic range of species until their extinction about two million years before the end of the Cretaceous. In the last years multidisciplinary studies on inoceramid shells have been carried out in the Basque-Cantabrian Basin including detailed geochemical analysis from platform to pelagic facies (C, O stable isotopes and minor element contents, e.g., Ca2+, Mg2+, Sr2+, Na+, Ba2+, Fe2+, Mn2+) (1, 2). Inoceramids supply the main biostratigraphic framework of the studied area which is correlated with other biozones (ammonites and planktonic foraminifera); mineralogical and geochemical signals recorded in the inoceramid shells and their host rocks have been used to further assess palaeoenvironmental conditions.

Coniacian and Santonian sequences contain an abundant record of Tethyan and cosmopolitan inoceramids, while boreal genera, such as Sphenoceramus, are not present. Only higher delta 18-O data supply tentative palaeotemperatures. Values from the Coniacian/Santonian platform sequences are 21.9ºC and 20.6ºC for surface and bottom waters, respectively, whereas those from the middle to upper Santonian deep basin sequences are 23,4ºC and 17,7ºC for surface and bottom waters, respectively. A palaeoclimatic cooling is reported in the Maastrichtian by the first occurrence of the boreal, cold-water inoceramid genus Spyridoceramus, which is supported by delta 18-O data (3). Although burial diagenesis affected the carbonate matrix and inoceramid shells, the isotopic signals reflect a trend towards positive values in both surface water masses (SWM) and intermediate water masses (IWM). A tentative palaeotemperature estimation on well-preserved shells indicates that Lower Maastrichtian SWM (21-22ºC) and IWM (18ºC) were warmer than SWM (17-18ºC) and IWM (12ºC) from the Lower/Upper Maastrichtian boundary.

(1) Gómez-Alday, J.J. 2002. Inocerámidos (Bivalvia): diagénesis e implicaciones paleoambientales. Maastrichtiense inferior. Unpublished PhD Thesis, Universidad del País Vasco, 232 pp.

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(2) Jiménez-Berrocoso, A. 2004. Petrología y geoquímica de inocerámidos (Bivalvia) y roca encajante en facies de plataforma y cuenca profunda (Coniaciense final-Santoniense superior, Cuenca Vasco-Cantábrica): contrastes diagenéticos e implicaciones paleoambientales. Serie Tesis Doctorales. Universidad del País Vasco, 459 pp.

(3) Gómez-Alday, J.J., López, G. and Elorza, J. 2004. Cretaceous Research 25 (5): 649-668.

A KEYSTONE LINK BETWEEN TWO CRITICALLY ENDANGERED SPECIES IN

EUROPEAN RIVERS: THE GIANT FRESHWATER PEARL MUSSEL

(MARGARITIFERA AURICULARIA SPENGLER) AND THE EUROPEAN SEA

STURGEON (ACIPENSER STURIO LINNAEUS)

López, M.À., Altaba, C.R., Rouault, T. and Gisbert, E.

(1) Aquatic Ecosystems Unit - Institut de Recerca i Tecnologia Agroalimentàries (IRTA). Generalitat de

Catalunya. Ctra. Poble Nou s/n, 43540 Sant Carles de la Ràpita, Spain.

(2) Laboratory of Human Systematics. University of the Balearic Islands. Ctra. Valldemossa, 07071 Palma de

Mallorca, Spain. (3) Estuarine ecosystems and diadromous fish research

unit,CREA. French Institute of Agricultural and Environmental Engineering Research (CEMAGREF), Moulin de Logerie, 33660 St Seurin sur l'Isle, France.

(4) Center of Aquaculture - Institut de Recerca i Tecnologia Agroalimentàries (IRTA). Generalitat de

Catalunya. Ctra. Poble Nou s/n, 43540 Sant Carles de la Ràpita, Spain.

Two of the most endangered aquatic species in western Europe are the giant freshwater pearl mussel Margaritifera auricularia (Spengler), and the European sea sturgeon Acipenser sturio (Linnaeus) (1). These large, long-lived animals were once widespread and coexisted in big rivers throughout the western Palearctic region. Owing to a combination of impacts on their habitat, both species suffered a precipitous decline and now survive far away from each other in relatively unspoiled refugia (2, 3). On the basis of their coincident ecological and geographical ranges and parallel historical declines, it was hypothesized (2) that the sturgeon was a major host and disperser of M. auricularia. In order to assess whether A. sturio can function as a host for M. auricularia, we artificially

infested two specimens kept at 18ºC in the French Estuarine Ecosystems Research Unit (CREA) in the Gironde with glochidia collected from naiads in the Ebro. Viable juveniles were released 19 days after infection. This result provides experimental evidence of a predictive biogeographical hypothesis, and it reveals an interspecific interaction that could play a keystone ecological role in pristine large-river ecosystems. We therefore strongly suggest to link recovery programs for the two species and to elaborate joint conservation and management guidelines.

(1) Baillie JEM, Hilton-Taylor C. and Stuart SN (eds.) 2004, IUCN Red List of threatened species. A global species assessment, IUCN, xxiv + 191 pp.

(2) Altaba CR 1990, Biological Conservation, 52: 271-286.

(3) Rochard E, Castelnaud G and Lepage M 1990, Journal of Fish Biology, 37 A: 123-132.

SYSTEMATIC REVISION OF THE GENUS CUCULLELLA MCCOY, 1851 (BIVALVIA:

NUCULOIDA)

Machado, D.M.d.C.

Laboratório de Estudos de Comunidades Paleozóicas, Departamento de Ciências Naturais, ECB, CCBS, UNI-RIO, Rua Pasteur, 458 sala 504 Urca Rio de Janeiro,

RJ, Brasil CEP:22240-290; deusana@unirio.br

McCoy (1) described the genus Cucullella to include Paleozoic Nucula-like forms without resilifer and with Arca-like hinge. Only in 1855 did McCoy (2) cite the Phillips & Salter's (3) species from Silurian rocks from United Kingdom, Cucullaea antiqua, C. ovata and Nucula coarctata, as belonging to Cucullella and distinguished this genus from Cleidophorus and Nuculites, American genera with very similar features. Following studies synonymized Cucullella and Cleidophorus as junior synonyms of Nuculites. The systematic revision of Nuculites enabled the revalidation the genus Cucullella and proposed an emended diagnosis based on its type-species Cucullella antiqua (Sowerby, 1839), designated by Beushausen (4). A different hinge structure, from that of Nuculites, a narrower dorsal internal ridge and a posterior radial sulcus allow to distinguished Cucullella from any anterior-plate nuculoid. This genus shows a stratigraphic distribution from Early Silurian to Late Devonian. Geographically, it was restricted to Avalonia and Laurentia during the Silurian, with an undetermined occurrence in Bolivia; in the Middle Devonian, this genus spread out to North Gondwana, becoming

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completely extinguished in the Late Devonian. The following species belong to Cucullella: C. antiqua, C. concentrica Hall, 1860, C. robusta (Williams, 1917), C. triquetra (Conrad, 1841), Cucullella? aff. C. triquetra (Conrad, 1841), Cucullella? nituda (Prouty), C. septulata (Babin, 1966), C. rotundata (Babin, 1966), Cucullella? sp. A and Cucullella? sp. B. This genus is included in the family Palaeoneilidae but not as proposed by Babin, Jauoen & Rachebouef (5) and seems to be phylogenically related to Arisaigia and Tropinuculites.

(1) McCoy F 1851, Annals and Magazine of Natural History, ser. 2, 7: 45-63.

(2) McCoy F 1855. Description of the British Palaeozoic Fossils in the Geological Museum of the University of Cambridge. University of Cambridge Press, 661p.

(3) Phillips J and Salter JW 1848, Memoirs of Geological Survey of Great Britain, 2(1): 359-369.

(4) Beushausen, L. 1895, Abhandlungen der Königlich Preussischen Geologischen Landesanstalt, new ser., 17, 514 pp + atlas.

(5) Babin C, Jauoen R and Racheboeuf P 2001, Palaeontographica, A 261: 1-54.

A PRELIMINARY PHYLOGENY OF THE EUROPEAN UNIONOIDEA

Machordom, A., Araujo, R., Nagel, K.O., Reis, J., and Toledo, C.

(1*, 2, 5) Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, 28006 Madrid,

Spain; rafael@mncn.csic.es; carlostc@wanadoo.es; annie@mncn.csic.es

(3) Dr.-Gremmelsbacher-Str. 6, D - 79199 Kirchzarten, Germany; konagel@gmx.de

(4) Centro de Biologia Ambiental / Dep. de Biologia Animal, Faculdade de Ciências da Universidade de

Lisboa, Campo Grande, C2, 1749-016 Lisboa, Portugal; jmc.reis@clix.pt

European unionoids are far less diverse than North American ones (that is, between 20 and 30 species versus ca. 300 species). Nevertheless, the taxonomy of European naiads is poorly resolved. Its starting point is the seminal paper from Haas (1969), Superfamilia Unionacea. Only 5 European genera have been described: Anodonta, Margaritifera, Microcondylaea, Potomida, Pseudanodonta and Unio, with only one or two representatives in each genus except Unio. In the past, unrecognised shell convergences and underestimated variability have led to a plethora of taxonomic names whereas molecular genetic

approaches have proved useful to discriminate different taxa or evolutionary units and to establish their phylogenetic relationships. With this in mind, we have undertaken molecular analyses of the European naiads in order to clarify their taxonomy, biogeographic distribution and phylogenetic relationships. Although we are studying samples from several European countries (Ireland, Greece, Russia, Turkey, Germany, Italy, Slovakia, Belgium and Switzerland), our more advanced results refer to the unionoids from the Iberian Peninsula. Almost 200 specimens from 12 taxa have been analysed for two mitochondrial genes: 16S RNA and cytochrome c oxidase subunit I. In order to develop the "cleanest" taxonomy possible, we concentrated, whenever possible, on specimens belonging to the terrae typicae of species and subspecies.

Our results, complemented by sequences from GenBank, indicate that Unio, Potomida, Microcondylaea and Margaritifera are monophyletic whereas monophyly of Anodonta is not supported. The genus Unio, which is represented by several (morpho-) species and subspecies, showed at least 10 evolutionary lineages more or less corresponding to: Unio cf. pictorum and U. cf. crassus, both endemic from the Iberian Peninsula, and their corresponding nominal sub/species, U. mancus mancus , U. mancus elongatulus, U. mancus bougeticus, U. cf. aleroni, U. tumidus and the African U. caffer.

EASY TO SEE, DIFFICULT TO DESCRIBE: TOWARDS A STANDARDISED DESCRIPTION

OF BIVALVE LARVAL SHELL SHAPE

Malchus, N.

Departament de Geologia, Area Paleontologia, Fac. de Ciències, Campus, Edifici Cs, Universitat Autònoma de

Barcelona, 08192 Bellaterra, Catalunya, España; n.malchus@gmx.net

Early ontogenetic shells of bivalves carry between 33 and 48 basic character sets/characters/states which could be successfully employed in taxonomy, evolution-developmental studies and a large number of derived applications. Unfortunately, the elementary taxonomic identificacion, in any case a specialist's task, is largely hampered by the heterogeneity of description modes. All modes include line drawings or photos of shape, specifically of the shell's contour, however. But contours are often very similar; differences may then still be perceived optically but are difficult to assess with respect to taxonomic importance and especially difficult to describe in a consistent, comparable way.

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The present contribution proposes a simple graphic method which should aid in an easier perception of significant differences and a more homogenous description.

High magnifying light and SEM microscope can be used. Prerequisites are the distinction of left and right valves and proper orientation of the specimen for length/height measurements and for a non-distorted photo from which the contour is drawn using a graphic program. Single valves are to be preferred. The present study has used left valves wherever possible, with the contour drawn from exterior view (contours drawn from LV interior and RV exterior must be mirror-flipped). Shell/valve length is defined as the longest anterior to posterior distance parallel to the hinge axis and height as the longest dorsal to ventral distance at 90º to the length axis. The contour must be rotated until the length axis lies horizontal before further treatment.

The final graphic is obtained after an easy-to-do 8-step procedure. It shows a white-filled contour on a black-filled circle (centred on the same point!); the circle diameter is the minimum required to completely enclose the contour and thus touching the contour at a single point (rarely more). This composite is superimposed by a cross also centred on the midpoint. Contours can then be compared and described referring to the quadrants which are counted clockwise: I = posterodorsal, II = anterodorsal, etc. The figure should be accompanied by a scale bar [examples in (1, 2)]. The procedure is here used for late larval stages but could be applied to any growth stage, allowing for example allometries of growth series to be visualised and compared. The long term objective would be to integrate such representations in determination keys, taxonomic bivalve web pages, and image analysis techniques. For this contours are classified referring to simple geometric figures such as oval, round, triangular, etc. [This is a contribution to Ramón y Cajal research contract (2001-2006) and to project number DGI-BTE2003-03606 of J. M. Pons (both Universitat Autònoma de Barcelona).]

(1) Malchus N and Warén A 2005, Marine Biology Research 1: 350-364.

(2) Malchus N 2006, The Nautilus 120: 8-14.

THE BIVALVE TOOTH PUZZLE: NON?-HOMOLOGY OF HINGE TEETH AND DENT-

LIKE STRUCTURES

Malchus, N.

Departament de Geologia, Area Paleontologia, Fac. de Ciències, Campus, Edifici Cs, Universitat Autònoma de

Barcelona, 08192 Bellaterra, Catalunya, España; n.malchus@gmx.net.

Taxodont-like and lamellar hinge teeth in Palaeotaxodonta, Pteriomorphia and Heterodonta, and isodont (spondyloid), dysodont (mytiloid), and trigonioid-type teeth are generally considered independent structures; tooth-like chomata and pectinoid microridges are not at all considered as teeth. However, they are all preceded by a larval to early postlaval taxodont-like dentition, here called generation 1 teeth (G1). Own SEM-based studies on early hinge ontogeny as well as literature data reveal that G1 can be co-functional with an adult tooth series (G2) and hence, that there exist two independent tooth-generating morphogenetic fields (MGF-1 and MGF-2). The almost ubiquitous distribution of the MGF1/2-pattern suggests that it is a rather old symplesiomorphy within the Bivalvia. In addition, literature data (1) on transposed hinges indicate that anterior and posterior MGF-2 have a certain (non-lethal) degree of independence in some heterodont lineages. If these hypotheses are correct, it should be ultimately possible to derive most or all tooth phenotypes of post-fordillan-pojetaian bivalves from MGF-1 and MGF-2, respectively.

This contribution presents observations on hinge ontogenies of post-palaeozoic pteriomorphs (mainly), carditoids and palaeotaxodonts, which are largely consistent with the two-phase hypothesis. Arcoids and a Jurassic dimyid show a larval G1a series, commonly continuous onto the early postlarval hinge plate (G1b series) (both MGF-1). G1b teeth often disintegrate and then disappear. The onset of the adult G2 series (MGF-2) is abrupt (crura of spondylids, plicatulids are likely G2). Comparable patterns are found in some Tertiary to Recent palaeotaxodonts and recent carditoids. The origin of adult teeth of Arca and Striarca is unclear [fused G1b, G1c (see mytilids), or G2]. Lamellar teeth of arcoid parallelodonts appear to consist of merging pustular G2 teeth; they grow in height by piling up pustules which results in the typical vertical striation of the lamella. This may be a key observation to interpret lamellar teeth of Ordovician pteriomorphs and palaeotaxodonts. Mytilids deviate from the two-phase pattern by presenting G1a, G1b (fuse easily), and what is presently coded G1c (all belonging to MGF-1) before the dysodont G2 teeth [cf. (2)]. Chomata as of pterioids-ostreoids and pectinoids are possibly G1c or remnants of G2. The homology with pectinoid microridges is presently not supported. Palaeozoic bivalves still require a profound review but it appears feasible to relate anterior teeth in heterodonts, cyrtodonts and cycloconchs to the anterior MGF-2. [This research contributes to Ramón y Cajal contract (2001-2006),Universitat Autònoma de Barcelona and to

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project number CGL2004-00802/BTE of A. Checa, Universidad de Granada, Spain.]

(1) Cox LR, 1969, p. N56-N58, In: Moore RC (ed.), Treatise on Invertebrate Paleontology. Part N. vol. 1. Mollusca 6. Bivalvia, The University of Kansas and The Geological Society of America, Lawrence, Kansas, 489 pp.

(2) Evseev GA, Semenikhina OY and Kolotukhina NK, 2005, Acta Zoologica Sinica 51: 1130-1140.

FIRST EVIDENCE OF A CALCITIC FOLIO-PRISMATIC PALAEOLOPHID "OYSTER"

FROM THE NORIAN OF WRANGELIA TERRANE, WESTERN CANADA

Malchus, N, Haggart, J.W., Pufahl, P.K., Tozer, E.T., Orchard, M.J., and Nixon, G.

(1*) Departament de Geologia, Universitat Autònoma de Barcelona, Spain; n.malchus@gmx.net

(2) Department of Earth and Ocean Sciences, University of British Columbia, Vancouver, British

Columbia V6T 1Z4 and Geological Survey of Canada, #101-605 Robson Street, Vancouver, British Columbia

V6B 5J3 Canada (3) Department of Geology, Acadia University,

Wolfville, Nova Scotia B4P 2R6 Canada (4, 5) Geological Survey of Canada, #101-605 Robson Street, Vancouver, British Columbia V6B5J3 Canada (6) British Columbia Geological Survey, PO Box 9333 Stn Prov Gov’t, Victoria, British Columbia V8W 9N3

Canada

Recent geological mapping on northern Vancouver Island has identified a fossil locality within a sequence of mixed-siliciclastic and calcareous sedimentary strata comprising the classic, Late Triassic Wrangellian stratigraphic succession. Several "oysters" - otherwise relatively uncommon in the Wrangellia terrane - were found at this locality together with ammonoids which suggest a late Early Norian age. Unexpectedly for a Triassic oyster, the specimens combine a Lopha-like morphology and ornamentation with what superficially appeared an entirely chambered shell, apparently originally filled with ostreid chalky deposits. This paper presents the geological context and discusses results from stable isotope, minor element, and cathodoluminescence analyses on the shell microstructure in the light of current hypotheses on microstructure evolution and the contentious taxonomic status of the Palaeolophidae (1-6).

Cathodoluminescence microfabrics and low Sr content (< 800 ppm) indicate that the shell was originally low Mg calcite and not aragonitic (nacreous) as species of Umbrostrea (2). This is the first geochemical indication that Lopha-like, entirely calcitic "oysters" co-occurred (in time not space) with the stratigraphically older Umbostrea stock at least since the late Early Norian. SEM analysis of shell treated with "Mutvei's solution" revealed that the shell originally consisted of calcite prisms throughout with internal foliated ultrastructure rather than of regular foliae with chalky deposits.

Comparisons with evolutionary microstructure changes in aviculopectinids, pectinoids, anomiids and gryphaeid oysters would thus suggest that calcitic folio-prismatic layers are evolutionary transitional between calcitic simple prims and regular + complex cross foliated shell layers. Folio-prismatic layers probably successively replaced nacre in oyster ancestors and/or early oysters. However, this interpretation does not resolve the question of whether foliate and nacreous Umbrostrea (2) and the present palaeolophid species indeed belong in the monophylum Ostreoidea, i.e. Gryphaeidae and Ostreidae.

(1) Carter JG 1990 (p. 220), In: Carter JG (ed.), Skeletal biomineralisation: patterns, processes and evolutionary trends, vol. 1: 832 pp, Van Nostrand Reinhold.

(2) Hautmann M 2001, Palaeontology 44: 339-378. (3) Márquez-Aliaga A, et al. 2005, Palaeo3: 127-136. (4) Esteban-Delgado F, et al. 2006, this volume. (5) Malchus N 1990, Berliner geowissenschaftl-iche

Abhandlungen, Reihe A, 125: 1-231. (6) Ó Foighil D and Taylor DJ 2000, Molecular

Phylogenetics and Evolution 15: 301-313.

NEOGENE DREISSENIDS IN CENTRAL EUROPE - EVOLUTIONARY SHIFTS AND

DIVERSITY CHANGES

Mandiç, O. and Harzhauser, M.

Geological-Paleontological Department, Natural History Museum Vienna, Burgring 7, 1010 Wien,

Austria - EU. (1*) oleg.mandic@nhm-wien.ac.at; (2) mathias.harzhauser@nhm-wien.ac.at

Neogene dreissenid evolution in central and south-eastern Europe is an eye-catching example for the impact of geodynamics on biotic radiations. Two already vanished paleogeographic entities provided the habitat for the conspicuous development at ~30-5 my. The Oligocene to Miocene Paratethys Sea and its late Miocene to Pliocene descendent Lake Pannon represent

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one of these aquatic systems. The latter was formed by the Oligocene to middle Miocene Dinaride Lake System. Both, partly coeval, waterbodies harbored radiations of dreissenid bivalves with several cases of parallel morphologic evolution.

The dreissenid faunas of each biogeographic unit display phases of high morphologic disparity with a time offset of at least 5 my. The ecological niches represented and life-strategies developed by dreissenid bivalves during that time is outstanding and unique for this group of now-a-days usually byssate filter feeding epibionts. Like their modern relatives, the Miocene dreissenids conquered freshwater habitats as well as brackish water but always avoided normal marine environments. Aside from a large number of "ordinary" byssate epibionts, the Miocene and Pliocene dreissenids developed lineages adapted to soft-bottom habitats. One group within Mytilopsis developed sediment-reclining strategies whilst the dreissenomyid flock even managed to penetrate the sediment by active burrowing. Filter feeding is suggested to have been the prevailing feeding strategy for Mytilopsis, Dreissena and the dreissenomyids throughout the considered interval. Congeria probably utilized chemosymbiosis as additional energy source. In total, stratigraphic and geographic data of about 200 Neogene dreissenid taxa (species and subspecies) have been distilled from the highly complex literature to show evolutionary trends and important changes in diversity patterns. The study represents partial results of the Austrian FWF-Project P18519-B17: "Mollusk Evolution of the Neogene Dinaride Lake System".

SPECIES OF EXOTICA (BIVALVIA: TELLINIDAE) FROM NEW CALEDONIA

Matsukuma, A.

The genus Exotica was proposed by Lamy with the type-species Tellina exotica Jousseaume in Lamy (= Tellina parvula Bertin, 1878, Nouv. Arch. Mus. Hist. Nat., [2], 1: 263, pl. 9, figs. 8a-c, 2 syntypes in MNHN, New Caledonia), Recent, Red Sea.

DIAGNOSIS: Shell small, cuneiform to antero-posteriorly elongate oval, twisted to right posteriorly. Hinge with two cardinal teeth, and anterior and posterior lateral teeth in the right valve. Opisthodetic parivincular ligament sunk between both valves. Resilium located just anterior of nymph. Pallial sinus deep, almost reaching anterior adductor scar. Anterior

adductor scar elongate oval; posterior adductor scar subquadrate. Internal shell margin outside of pallial line broad.

REMARKS: 55 syntypes of T. exotica are stored in MNHN, Paris. Among the syntypes, 50 shells represent one species; the remaining 5 shells represent 4 different species. One of the 50 specimens will be selected as lectotype of T. exotica. The species was considered conspecific with Tellina triradiata H. Adams, 1870 (1-3) and was placed in the subfamily Macominae (2). However, T. exotica differs from T. triradiata in having a small resilium posterior to the cardinals and lateral teeth in the right valve; it should therefore be placed in the Tellininae (3-4). Semelangulus Iredale, 1924 is a subjective junior synomy of Exotica.

Tellinid shells collected by P. Bouchet (MNHN) and his colleagues in New Caledonia include Exotica parvula, E. fijiensis (Sowerby, 1868) and 4 possibly undescribed Exotica species. Exotica parvula has thick, more or less bilaterally compressed, wedge-shaped shells. Anterior margin rounded; posterior margin narrowly truncated. Outer surface ornamented with regularly spaced fine commarginal lamellae at the anterior to middle portion, stronger posteriorly. Anterior dorsal edge of left valve long and straight, inserted to anterior lateral socket of right valve. Exotica parvula is known from Suez, Perim Island, Red Sea and New Caledonia (Koumac). Exotica fijiensis has small, thick, bilaterally compressed shells. Umbo low, located on a third to posterior margin. Hinge plate wide. Outer coloration creamy white with translucent and opaque dashes. Outer surface ornamented with regularly spaced fine commarginal lamellae. Exotica fijiensis is known from Hawaii, Ponape, New Caledonia, (Koumac) Fiji and Cocos-Keeling Island.

(1) Lamy, E. 1918, Bull. Mus. Hist. nat., 24: 116-124. (2) Keen, M. 1969, In: Cox, L. R. et al. (eds.): Treatise

on Invertebrate Paleontology, part N, 2: 613-628. (3) Habe, T. 1977, Systematics of Mollusca in Japan,

Zukan-no-Hokuryukan, 372 pp. (4) Oliver, P. G. 1992, Bivalved Seashells of the Red

Sea, Christa Hemmen, 330 pp.

PHYLOGENY OF VENEROIDEA (HETERODONTA) BASED ON

MORPHOLOGY AND MOLECULES

Mikkelsen, P.M., Bieler, R., Kappner, I., and Rawlings, T.A.

(1*, 2, 3) Department of Zoology, Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL

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60605-2496 USA; (4) Department of Biological Sciences, Florida

International University, Miami, Florida 33199, USA

The largest Recent family of Bivalvia, the marine Veneridae with about 800 species, comprises one of the least understood and most poorly defined molluscan taxa, despite including some of the most economically important and abundant bivalves, e.g., quahog, Pismo clams, and Manila clams. A review of previous phylogenetic analyses including superfamily Veneroidea (Veneridae, Petricolidae, Glauconomidae, Turtoniidae, Neoleptonidae) and within Veneridae shows minimal taxon sampling leading to weak conclusions and few supported synapomorphies.

New phylogenetic analyses on 114 taxa tested monophyly of Veneroidea, Veneridae, and 17 nominal venerid subfamilies, using morphological (conchological, anatomical) data and molecular sequences from mitochondrial (16S, COI) and nuclear (28S, histone 3) genes. Morphological analyses using 45 exemplar taxa and 23 traditional characters were highly homoplastic and failed to reconstruct traditional veneroid classification. Full morphological analyses (31 characters) supported monophyly of Veneroidea and Veneridae but only when certain taxa were excluded, revealing analytical difficulties caused by a suite of characters associated with neotenous or miniaturized morphology. Molecular analyses resulted in substantially higher clade consistency. The combined molecular dataset resulted in significant support for a particular topology. Monophyly of Veneridae is supported only when Petricolidae and Turtoniidae are subsumed, and recognized as subfamilies with derived or neotenous morphologies, respectively. Morphological character mapping on molecular trees retained a high level of homoplasy, but revealed synapomorphies for major branch points and supported six other subfamily groups (Dosiniinae, Gemminae, Samarangiinae, Sunettinae, Tapetinae, combined Chioninae + Venerinae). Glauconomidae and Neoleptonidae are provisionally maintained in Veneroidea pending further study.

HABITAT SELECTION OF MARGARITIFERA AURICULARIA AND OTHER NAIADS IN THE

CANAL IMPERIAL DE ARAGÓN, SPAIN

Nakamura Antonacci, K., Guerrero Campo, J., Zapater Galve, M., and Catalá Roca, C.

(1*, 3, 4) SODEMASA, Av. César Augusto, Nº 14, 8ª planta, 50004, Zaragoza,

España;knakamura@sodemasa.com (2) Departamento de Medio Ambiente del Gobierno de Aragón; Servicio

Provincial de Zaragoza, Plaza San Pedro Nolasco, nº 7, 50071, Zaragoza. España; jguerrero@aragon.es

Margaritifera auricularia is presently one of the most threatened European freshwater bivalve with its largest population inhabiting the Canal Imperial de Aragon in Spain. It here co-occurs with three other unionid species: Unio mancus, Anodonta sp. and Potomida littoralis. One of the main objectives, involved in a general Margaritifera auricularia Conservation and Recovery Plan of the regional government, is the habitat characterization of these species. This will serve to determine the specific ecological requirements in order to implement breeding in captivity and to design a habitat restoration management that ensures the survival of the species. Taking advantage of reparation works in the Canal Imperial, three habitat zones were sampled, accounting for a total length of 1400 m. Sampling included a visual/tactile review of 100 m long transects and substrate characterization of squares of 50 x 50 cm around the individuals in the bed centre and margins. For a quantitative approach, we used a canonical community ordination assessment (CANOCO).

The results show a clear preference of species for a particular microhabitat, especially associated with the substrate type. Canal banks characterised by slow water flow and deposition of suspended matter are preferentially inhabited by Anodonta sp. The bed centre with faster water flow and gravel and stones appears to be the exclusive habitat for M. auricularia (100 % of its individuals) whereas P. littoralis is represented by 80-90% and U. mancus by 50-60%. The last two species are more flexible regarding the changing conditions of the microhabitats as they are also found in intermediate habitats between the river banks and the river centre, and they survive in substrates dominated by mud where M. auricularia is not found. Concurrent with these observations, the CANOCO analysis locates M. auricularia far away from the other three species indicating that this species requires substrates with abundant rolling stones.

BIODEPOSITIONAL RATE OF THE MUSSEL MYTILUS CHILENSIS AND ITS EFFECTS ON

THE BIODIVERSITY OF BENTHIC COMMUNITIES

Navarro, J.M., Urrutia, G.X., and Clasing, E.

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(1*, 2, 3) Instituto de Biología Marina "Dr.Jürgen Winter", Universidad Austral de Chile, Valdivia, Chile;

(1*) jnavarro@uach.cl

Aquaculture activity of the mussel Mytilus chilensis has increased significantly during the last decade in the south of Chile (over 100,000 tons in 2005). The large amount of biodeposits (mainly faeces) produced by the bivalves under suspended culture can affect the bottom communities, modifying the texture and organic content of the bottom sediments and changing the fauna species diversity. The objective of the present study was to know the effects of the biodeposition rate of a massive culture of the mussel Mytilus chilensis on the biodiversity of the benthic communities.

Three areas (A-C) with different grades of impact were monitored seasonally at the Yaldad Bay (43°08'S;73°44'W). These areas differ significantly in the sediment composition, area A (more affected by the mussel culture) being characterized by fine sediment (mud = 58-87 %) and Areas B and C (less affected) containing > 85% gravel and sand. The analyses of carbon and nitrogen contained in the sediments showed a similar pattern, with significant higher values for area A. Significant differences were also found in the faunal composition: area A shows the lowest number of species with polychaetes being the main group of invertebrates. The two other areas (B and C) presented larger number of species with Crustacea being the most important group, followed by polychaetes, molluscs and equinoderms. Species diversity was also different between places, area A showed the lower indices of biodiversity along the year. It is concluded that the massive culture of mussels affect significantly the benthos, modifying the sediment composition and reducing species diversity. [funded by DID-UACH; MECESUP USC 0303.]

RESTORATION OF ENDANGERED FRESHWATER BIVALVES IN THE UNITED

STATES

Neves, R.

Virginia Cooperative Research Unit, Dept. of Fisheries & Wildlife Sciences, Virginia Tech University,

Blacksburg, VA 24061, USA.

The U.S. Bureau of Fisheries established its first freshwater mussel propagation facility at Fairport, Iowa on the Mississippi River in 1914, in response to overharvest of shells for the pearly button industry. Although this Fairport Biological Station provided 2

decades of research on reproductive biology, host fish identification, and techniques to mass-produce juveniles, the staff was unable to develop reliable methods for culturing juveniles to larger sizes for release to the wild. This research topic lay dormant for nearly 50 years until a suite of mussel species was listed in the mid-1970's. These newly listed species provided the impetus for a second surge of research activity, to understand the causes for decline and to reverse downward trends in population abundance and prospective extirpation or extinction.

Propagation and restoration of the 70 federally endangered and threatened mussel species in the U.S. began 9 years ago, with the successful culture and release of endangered tan riffleshells by the Freshwater Mollusk Conservation Center (FMCC) at Virginia Tech. Using recirculating aquaculture systems, the FMCC has focused on the 37 protected species of the Tennessee River system in the southeastern U.S. and has successfully conducted host fish research and propagation of 25 of those species. Since 1997, an additional 14 federal and state-operated facilities have conducted life history or propagation studies and have released more than 1 million juveniles of rare species in the Mississippi River system and several other rivers. Each facility has its own site-specific conditions for propagation, using available water resources and culture systems designed or modified at fish culture stations, research laboratories, or makeshift facilities to accommodate available space, personnel, and budgets. Production systems for juveniles are typically banks of aquaria to hold host fish infested with glochidia for the transformation period. Sizes and numbers of fish dictate size and arrangement of tanks. Some systems are manually siphoned, whereas others such as AHAB (Aquatic Habitats) units are modified with screens to facilitate daily recovery of transformed juveniles. Recently developed at Missouri State University is a compact recirculating system (mucket bucket) that occupies minimal space as nested buckets, with a manifold system for delivering algal suspensions at controlled rates. Diet development for juvenile mussels continues to progress, with a variety of unicellular algae shown to provide adequate nutrition, as well as commercially available microalgae concentrates used by the marine shellfish industry. A diet development research program at White Sulphur Springs National Fish Hatchery, West Virginia, now includes a tubular reactor capable of continuous algal culture.

In addition to off-site propagation facilities, the endangered Higgin's-eye mussel in the upper Mississippi River is being propagated using in-situ fish-holding cages to allow juveniles to drop to cage bottoms where they can be collected after metamorphosis and growth. This cage culture method has been very

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successful for this species and is dramatically enhanced recruitment at sites of cage deployment. More than 11,000 juveniles have been harvested from cages, with sexually mature adults in 2006 from the cohorts produced in 2002-2003. The future of mussel propagation for recovery is bright in the U.S., and the methods are readily applicable to other mussel species worldwide.

GENETIC RELATIONSHIPS AMONG JAPANESE AND KOREAN POPULATIONS

OF CULTURED PACIFIC OYSTER

Okimoto, T. and Aranishi, F.

(1*, 2) Department of Biological and Environmental Sciences, Miyazaki University, Miyazaki 889-2192,

Japan; (1) okimoto@cc.miyazaki-u.ac.jp

The Pacific oyster Crassostrea gigas naturally occurs in Japan, Korea, Taiwan, and China, and is one of the dominant species of shellfish aquaculture in East Asia. Since the first development of raft for hanging culture techniques in 1925 in Japan and the first introduction of raft and suspended long-line culture techniques in the 1960s in Korea, the oyster production increased to reach approximately 220 and 209 thousand metric tons in 2000, respectively (1). During this period, the oyster production had sometimes declined due to overexploitation, infectious diseases, and deteriorated water quality. In order to counteract such crisis and sustain the oyster production, adult and spat oysters have been transplanted not only in Japan and in Korea but also between the two countries. As a result, increasing interest in the genetic basis of cultured oyster stocks has urged us to compare population structures in the major production areas in Japan and Korea for providing useful information for resource management. In the present study, we thoroughly examined the genetic relationships of cultured Pacific oyster among two Japanese stocks such as Hiroshima and Miyagi, both of which accounted for approximately 71 % of the domestic oyster production (2), and two Korean stocks such as Koje and Goseong, where had long been the largest oyster grow-out areas (3,4), by means of molecular biological techniques based on mitochondrial DNA analysis (5-7).

(1) FAO 2003, Review of the State of World Aquaculture, FAO Fisheries Circular, No. 886, Rev. 2, 95 pp. (2) MAFF 2004, Annual Statistics on Marketing of Fishery Products, Statistics and Information Department, Ministry of Agriculture, Forestry and Fisheries, 428 pp.

(3) Kang CK et al. 2000, Journal of Shellfish Research 19: 771-778.

(4) Kang SG et al. 2003, Journal of Experimental Marine Biology and Ecology 282: 1-21.

(5) Aranishi F & Okimoto T 2004, In: Hendry CI (ed.), Aquaculture Canada 8: 15-19.

(6) Aranishi F & Okimoto T 2005, Journal of Applied Genetics 46: 201-206.

(7) Okimoto T 2006, Ph.D. Thesis, Nagasaki University, 79 pp (in Japanese).

MORPHOLOGICAL BASIS TO SYSTEMATICS OF THYASIRIDAE

Oliver, G.

National Museum of Wales; Graham.Oliver@museumwales.ac.uk

The thyasirid shell is relatively devoid of characters, such as sculpture and dentition, which are used to define species and genera and anatomical data has seldom accompanied their descriptions. Consequently, there is considerable taxonomic confusion at both levels. This is evidenced in the different use of generic names between faunas and the often inappropriate widespread use of species names such as Thyasira flexuosa. New anatomical data on the ctenidial morphology and molecular data are becoming available both suggesting that the current genera are inadequately defined. In order to revise the Thyasiridae a new morphological review is needed. In this paper the nominal genera are examined and their stability and current definition are discussed. Examples of species problems are also given and the apparent wide geographical and bathymetric ranges of species are discussed.

AN UNUSUAL CASE OF GENDER-ASSOCIATED MITOCHONDRIAL DNA

HETEROPLASMY: THE MYTILID MUSCULISTA SENHOUSIA (MOLLUSCA:

BIVALVIA)

Passamonti, M. and Scali, V.

Department of "Biologia Evoluzionistica Sperimentale", University of Bologna, via Selmi 3, I-40139 Bologna,

Italy; (1*) mpassa@alma.unibo.it

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A new case of Doubly Uniparental Inheritance (DUI) of mitochondrial DNA is described in the mussel Musculista senhousia (Mollusca: Bivalvia: Mytilidae). Its heteroplasmy pattern, showing male (M) and female (F) mitochondrial haplotypes, is in line with standard DUI. However, one trait appears absolutely unexpected: F haplotypes sequence variability is significantly higher than that of M haplotypes. This is the first time that such feature is observed in a DUI system, and it is challenging most of the rationales proposed to account for sex-linked mtDNA evolution. Moreover, the system, tested for F mtDNA variability in somatic tissues, shows that F mitochondrial haplotypes experience a higher mutation rate in males than in females, thus suggesting that there might be some mechanism to keep a low mitochondrial DNA mutation rate in females. This fits well with evolutionary predictions: antioxidant gene complexes, evolved to protect mitochondria from oxidative damages, might be under relaxed selection in males. Phylogenetic analysis clusters together M and F types, suggesting that M. senhousia may have experienced 'masculinization' events, occurring in the lineage leading to the taxon; this also suggests that during the evolutionary history 'masculinization' might have been present in mytilids, other than Mytilus.

IMPROVING KING SCALLOP (PECTEN JACOBAEUS) SPAT COLLECTION BY THE

BAG COLLECTOR

Peña, J., Saavedra, C., and Cordero, D.

(1*, 2, 3) Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas, Ribera

de Cabanes, 12595 Castellón, Spain; (1) jbpenya@iats.csic.es

Since recent years we are deploying filamentous collectors to catch pectinid larvae in a fish farm located at a depth of 28-33 m on sand bottom (40º 04'N, 0º 10'E) in Castellón waters (western Mediterranean). We have tested two kinds of bags: the raschel bag (42x46 cm), which was used in the last years and have a pore size of 16 mm contains two polyethylene net fragments of 41x42 cm, and the Chilean onion bag (66x41 cm) with 2 mm pore mesh which contains four net fragments. Collectors were positioned on March 14th and retrieved on June 13th 2005. The collector lines were attached to the fish farm structure with an 8 kg weight two meters above the sea floor. Seven bags were attached in each collector line from 3 m to 6.6 m above the bottom. In raschel bags three commercial pectinid species were attached: Pecten jacobaeus, Aequipecten

opercularis and Mimachlamys varia, meanwhile in Chilean bags some other species were found such as Crassadoma multistriata and Flexopecten flexuosus. The number of scallop spat per bag was 17-fold higher in Chilean bags instead of two-fold, as expected. The mean number of Pecten jacobaeus per bag was 0.95 in raschel bags versus 16.33 in Chilean bags. The percentage of Pecten jacobaeus among other pectinid species was 4.7% in raschel bags and was 15.5% in Chilean bags. The highest spat percentage was found for Aequipecten opercularis (75.5%) and Mimachlamys varia (35.7%), respectively. In general, Chilean bags retain higher amounts of pectinid spats because of their smaller pore size. However, some crab species, mostly Eriphia verrucosa, are also more retained, because they cannot escape. In fact, the average amount of crabs per bag in Chilean bags was 5.7, whereas there were only 0.2 in raschel bags.

STATE OF THE ART AND PROPOSALS FOR A REVISED CLASSIFICATION OF RADIOLITID RUDIST BIVALVES

Pons, J.M. and Vicens, E

(1*,2) Universitat Autònoma de Barcelona, Facultat de Ciències, Departament de Geologia, Campus, Edifici

Cs, 08193 Bellaterra, Spain; josepmaria.pons@uab.es

enric.vicens@uab.es

Radiolitidae d’Orbigny is one of the rudist families whose members seem to shear a number of synapomorphies allowing to be considered a monophyletic group (1). Some of these characters are related to the outer shell layer, particularly to its structure, and their variation was used to recognize subfamilies in the Treatise (2).

Constructional morphology analysis and revaluation of the outer shell layer in radiolitids shows: (a) that there are several models of outer shell layer structure (compact, continuous radial ridges, discontinuous radial ridges, normal cellular, cellular with radially elongate cells, discontinuous cellular, and discontinuous cellular with elongate cells) and (b) that all morphological aspects of the outer shell layer are a consequence of the spatial characteristics (development, folding, and stacking) of the growth lamellae; also, (c) that some of the characters used to distinguish subfamilies in the Treatise (2) were based on misinterpretations. Although some morphological characters of the growth lamellae may be preferentially associated with a particular growth lamellae structure, most do not. Some variations

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both in structure and morphology may be attributed to ecological factors but always preserving the ‘original’ model that can be easily identified and its variation interpreted.

Compact structure is present in all radiolitids outer shell layer. Radial ridges and polygonal cells appear as the main non compact structural models of growth lamellae structure, and there are no constructional or temporal evidences for considering one as derived from the other. We propose to distinguish two subfamilies according to the outer shell layer structure, one characterised by radial ridges and the other by polygonal cells in the growth lamellae structure. Eoradiolites is an example of the former and Radiolites of the last. Another taxon could probably be differentiated within the second, characterised by discontinuous cells as Chiapasella.

Most other characters of the outer shell layer (dipping, folding, and invaginations of the growth lamellae, radial structures, etc., and also canals) may represent convergences as far as they may occur simultaneously in different ‘clades’. Most of these characters show evident polarity and may be of incontestable value in future cladistic analyses when the possible convergences are clearly assumed and the analysis adequately pondered.

(1) Skelton PW and Smith AB 2000. In Harper EM et al (eds) The Evolutionary Biology of the Bivalvia. Geological Society, London, Special Publications 177: 97-127

(2) Dechaseaux C and Coogan AH 1969. In Moore RC (ed.) Treatise on Invertebrate Paleontology, Part N. Mollusca 6, Bivalvia (2 of 3). Geological Society of America and University of Kansas Press: N803-N817.

IS THE INTER-ANNUAL RISING OF ALLELIC RICHNESS IN NATURAL

POPULATIONS OF MYTILUS GALLOPROVINCIALIS RELATED TO THE

PRESTIGE OIL SPILL?

Presa, P., Llavona, A., Pérez, M., Seoane, A., Lado-Insua, T., and Diz, A.

University of Vigo, Faculty of Biology, Department of Biochemistry, Genetics and Immunology, 36310 Vigo,

Spain; pressa@uvigo.es

The sinking of the tanker Prestige in November 2002 off the coast of Galicia resulted in the release of heavy oil. This spill led to a serious environmental impact in the area which biological consequences are stillbeing

assessed. In this study we have tried to shed light on how the heavy oil could have affected the genetic diversity of Mytilus galloprovincialis, a species ubiquitously distributed along Galician coasts. The intuitive hypothesis about the oil effect on mussel populations is a putative erosion of its genetic diversity. This erosion can be assessed with highly variable markers such as microsatellites, analysed on temporal samples collected long before, during, and long after the Prestige sinking. The results obtained with seven microsatellites did not show any significant change in allele frequencies, neither between years nor between the localities sampled. Moreover, larger allele richness has been observed in some localities after the spill. This gain of genetic diversity could be owing to an increment of mutagenic events enhanced by the heavy oil or to natural population dynamics. [Funded with Xunta de Galicia project PGIDIT04RMA312002PR and sponsored by Hucoa-Erloss España.]

COMPARATIVE ECOLOGICAL STUDY OF TWO PARAPATRIC SPECIES OF GENUS ISOGNOMON (BIVALVIA: PTERIOIDEA) FROM THE SOUTHERN PART OF KHUNG

KRABEAN BAY, CHANTABURI PROVINCE, THAILAND

Printrakoon, C. and Tëmkin, I.

(1*) Department of Biology, Faculty of Science, Mahidol University, Rama VI Road, Phayathai,

Bangkok, Thailand; cheewarat040@hotmail.com (2) Division of Invertebrate Zoology, American Museum

of Natural History, Central Park West at 79th Street, New York, New York 10024; ilya@amnh.org

Multiple ecological parameters (distribution, density, biomass, substratum preference) were evaluated for two populations of Isognomon spp. leaving in parapatry in the adjacent Rizophora and mudflat zones of the mangrove ecosystem of Khung Krabean Bay, Thailand. Separated initially by ecological criteria, the two populations display substantial invariable anatomical differences as well as are clearly separable by morphometric analysis of shell shape providing the grounds of distinguishing these populations as two distinct species. The marked differences in shell shape and thickness, and byssus organization are hypothesized to be adaptations to different substrate preference resulting in different special organization of mudflat and mangrove communities. This difference is possibly responsible for the observed dissimilarity in the pattern

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and relative success of predation in the two zones. Moreover, the associations formed by conspecific individuals of the Isognomon spp. in mangrove and mudflat habitats create microhabitats for different arrays of epibionts by providing substrata for attachment and forming crevices between densely stacked shells. This study is the first contribution to the study of pterioidean bivalves of Khung Krabaen Bay, Chanthaburi Province on the east coast of the Gulf of Thailand. This is also the first case of identifying two distinct, albeit alike, species of mangrove-associated Isognomon in Thailand. The results of this analysis suggest that ecological criteria are important in identifying potential cryptic species and indicate the need for taxonomic re-evaluation of genus Isognomon.

(1) Harper E and Morton B 1994. In Morton B (ed). The Malacofauna of Hong Kong and Southern China III. Hong Kong University Press, Hong Kong: 405-425.

(2) Reid RGB 1985. In Morton B and Dudgeon (ed). In the Malacofauna of Hong Kong and Southern China II, Hong Kong Universirt Press. Hong Kong: 311-319

(3) Siung AM 1980. Bulletin of Marine Science 30(1): 90-101

SPATIAL VARIABILITY OF A CALLISTA CHIONE POPULATION IN THE WESTERN

MEDITERRANEAN

Ramón, M., Maynou, F., and Beata, M.

(1*) Centre d'Aqüicultura (IRTA), Crta. Poble Nou s/n, St. Carles de la Ràpita 43540, Spain;

mramon@icm.csic.es (2) Centre Mediterrani d'Investigacions Marines i Ambientals (CMIMA-CSIC), Passeig Marítim de la

Barceloneta, 37-49, 08003 Barcelona, Spain (3) ECOPROGES S.L., Llull 109, 08005 Barcelona,

Spain.

The venerid Callista chione is a commercial bivalve fished along the Mediterranean French coast, the Gulf of Trieste and the Greek coast (1). In Catalonia, smooth clam fishery is performed between the Tordera and Besós Rivers, on coarse sand bottoms at depths between 5 and 30 meters. This activity is conducted by twelve artisanal vessels which catch around 250 tonnes/year. The objective of this study is to analyse the spatial distribution of Callista chione recruits and the commercial fraction in number and weight. In order to cover the entire fishing ground, we established 16 transects perpendicularly to the coast at 4 km intervals

and at 5, 10, 20 and 30 m depth intervals. On these, we located a total of 50 sampling stations by GPS which were sampled employing four types of gears: two commercial ones provided with a steel mesh size (24x24 mm) and two experimental ones with mesh size of 12x12 mm to estimate recruitment. Sediment was also sampled. The spatial model of C. chione densities was calculated by Regression Kriging (2). This approach consists in building a deterministic model for the trend, by Generalized Linear Regression (GLM) or Generalized Additive Models (GAM), and kriging the residuals. The possible non-linearities between the dependent variable (density) and the continuous explanatory variables were captured by including quadratic terms in the GLM model and building thin-plate smoothing splines in the GAM model.

Our results show that C. chione is not uniformly distributed across the fishing ground. The response of density with depth is bimodal, with 2 high-density peaks at around 10 and 22 m depth, whilst the relationship with median bed-sediment size is linear (higher density with higher values of D50). Maximum densities have been found in the northern part of the study area and very low values, even absence, in the southern part. The density map of C. chione recruits shows the same pattern.

(1) Metaxatos A 2004. Journal of Sea Research 52: 293-305.

(2) Bishop TFA and McBratney AB 2001. Geoderma 103: 149-160

ATLAS OF THE FRESHWATER BIVALVES OF CONTINENTAL PORTUGAL

Reis, J.

Centro de Biologia Ambiental / Dep. de Biologia Animal, Faculdade de Ciências da Universidade de

Lisboa, Campo Grande, C2, 3º Piso, 1749-016 Lisboa, Portugal; joaqreis@gmail.com

In 2001 the Portuguese Institute for Nature Conservation initiated a project with the objective to produce an atlas of the freshwater bivalves occurring in continental Portugal. This project allowed to take important steps forward on the knowledge of this group. We here describe the main results of this project, including a species checklist, their distribution, ecology and conservation status. Since the last comprehensive study in the country had been carried out in 1941 (1), most areas of knowledge had to be addressed. In order to collect the maximum of available data we analysed all previous bibliographic references and studied the

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collections of the Natural History Museums of Lisbon, Coimbra, Porto and Madrid; private collections and personal communications were also used. Based on this information, we started an extensive sampling campaign in 344 sampling stations to validate existing references and cover poorly known geographic areas. Systematic studies, both morphological and molecular were necessary to clarify the taxonomy of the Unionidae family.

A total of 16 species were recovered belonging to four families: Margaritifera margaritifera (Family Margaritiferidae), Anodonta anatina, Anodonta cygnea, Potomida littoralis, Unio cf. crassus, Unio cf. pictorum (Family Unionidae), Corbicula fluminea (Family Corbiculidae), Sphaerium corneum, Musculium lacustre, Pisidium amnicum, P. casertanum, P. henslowanum, P. milium, P. nitidum, P. personatum, P. subtruncatum (Family Sphaeriidae). The possibility of occurrence of a second Corbicula species (Corbicula fluminalis) remains, located in the estuary of the river Tejo. Some previous records were considered to be erroneous (Dreissena polymorpha, Pseudunio auricularia, Sphaerium rivicola, Unio wolwichi) while the presence of Pisidium obtusale, identified by Favre (1943) (2) could not be confirmed. Data on the distribution, ecology and conservation for all species are given, and proposed conservation status based on IUCN (2000) (3) criteria are suggested.

(1) Nobre A 1941. Fauna malacológica de Portugal II. Moluscos terrestres e fluviais. Memórias e Estudos do Museu da Universidade de Coimbra 124:1-278.

(2) Favre, J. 1943. Revision des espèces de Pisidium de la collection Bourguignat du muséum d'histoire naturelle de Genève. Revue Suisse de Zoologie 50:1-64.

(3) IUCN 2000. The IUCN Red List of Threatned Animals. IUCN, Gland, Switzerland and Cambridge, UK.

PATTERNS OF DISTRIBUTION AND POPULATION STRUCTURE OF

MARGARITIFERA MARGARITIFERA (L.) (UNIONOIDEA: MARGARITIFERIDAE) IN THE TUA WATERSHED (NE PORTUGAL)

Reis, J.

Centro de Biologia Ambiental / Dep. de Biologia Animal, Faculdade de Ciências da Universidade de

Lisboa, Campo Grande, C2, 3º Piso. 1749-016 Lisboa, Portugal; joaqreis@gmail.com

The freshwater pearl mussel Margaritifera margaritifera (L.) was discovered in the Tua watershed in 2001 (1). This work describes the population studies undertaken to evaluate the impact of dams construction. The watershed is located in the region of Trás-os-Montes (NE Portugal), and discharges its water on the northern margin of the Douro river. It was until recently well preserved, with few dams and human activities affecting it. This situation is changing, with the construction of two major dams and pressure for additional dam construction due to the high hydrological regime of its rivers. Margaritifera margaritifera was known from three rivers, Mente, Rabaçal and Tuela, but the area where the mussels occurred in the first one was completely flooded by one of the recent dams. The patterns of occurrence of the species was studied on the whole watershed using a transect / quadrate method (2) and the population structure using the method of Hendelberg (1961) (3).

The mussels were unevenly distributed over the rivers showing a very aggregated nature. A detailed study of the downstream end of the Tuela population was made, counting all visible mussels over a stretch of 1600 m of river. The results show an extremely aggregated pattern severely impacted by an existing small dam. A total of 3910 mussels were counted, 3776 of which occurred within a stretch of 585 m not affected by the dam. Variable sized groups were found, mostly at the banks of the river. The population structure did not differ significantly between different groups of mussels. As a consequence of this study it was concluded that the Tuela river population is probably underestimated, and that the transect / quadrate methods described by (1) are not the most adequate for the study of this kind of populations.

(1) Reis J 2003. Biological Conservation 114: 447-452. (2) Young M, Cosgrove PJ, Hastie L, and Henninger B

2001. J. Moll. Stud. 67: 395-405. (3) Hendelberg, J. 1961. Report of the Institute of

Freshwater Research, Drottingholm 41: 149-171.

PLIOCENE PECTINIDS OF THE CADIZ PROVINCE (SW SPAIN)

Rico García, A., González-Delgado, J.Á., Civis, J., Aguirre, J., and Alonso-Gavilán, G.

(1*-5)Science Faculty, Dpto. of Geology (Paleontology), Pz. Merced, s/n 37008, Salamanca

(Spain); Alberi25@terra.es

Pliocene assemblages of pectinids (Pectinidae, Bivalvia) have been studied in ten stratigraphic sections in the

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southwestern margin of the Guadalquivir basin in the Spanish provinces of Cádiz and Sevilla. This part of the basin is characterised by a progressive shallowing-upward trend during the late Neogene (1, 2). More than 20 pectinid species have been identified with a varying species richness among the studied sections. Some sections contain Manupecten pesfelis, Flexopecten flexuosus, Palliolum excisum, Flabellipecten bosniasckii and Flabellipecten flabelliformis thus reinforcing the Pliocene age established for these deposits (1). Their presence allows to assign most of the studied sediments to the MPMU1 biozone (base of early Pliocene to top of middle Pliocene).

From a palaeoenvironmental point of view, the sediments of all sections indicate shallow-water inner shelf settings. However, within this general setting, the sedimentologic features and pectinid assemblages of some sections suggest sheltered low-energy palaeoenvironments with low sedimentation rates whereas others show an upward change from silty fine-grained sands to a massive accumulation of rhodoliths. This latter trend is accompanied by a change from Palliolum hyalinum, a typical inhabitant of low-energy outer shelf settings to Flexopecten spp. and Chlamys varia, which are characteristic of high-energy shallow-water shelf areas (1).

(1) Aguirre J 1995, Revista de la Sociedad Geológica de España 8: 153-166.

(2) Sierro FJ et al. 1996, In: P Friend y CJ Dabrio (eds.), Tertiary basins of Spain, Cambridge University Press, 329-334.

(3) Monegatti P y Raffi S 2001, Palaeogeography, Palaeoclimatology, Palaeoecology 165: 171-193

THE REDISCOVERED BIVALVE TYPE MATERIAL OF H. E. ANTON

Rogalla, N.S. and Schniebs, K.

(1*, 2) State Collections of Natural History Dresden, Museum of Zoology, A. B. Meyer-Bau, Koenigsbruecker

Landstr. 159, D-01109 Dresden, Germany, (1) rogalla@snsd.smwk.sachsen.de; (2)

katrin.schniebs@snsd.smwk.sachsen.de.

Hermann Eduard Anton (1794-1872, born at Goerlitz, Germany) was one of the most distinguished Saxonian malacologists of the 19th century. He was an amateur collector who earned his living as a bookseller, but who was deeply interested in mineralogy, palaeontology and malacology. His private collection contains fossil and Recent molluscs as well as corals, sea stars and sea urchins, all in all 4412 species with 13500 individuals.

Anton stood in high regard among other malacologists of his time and communicated regularly with Pfeiffer, Küster, Philippi and others. This reputation is also reflected by the fact that 15 species are named after him. He received a degree of honour of the Academy of Natural Sciences at Philadelphia. His major work, "Verzeichniss der Conchylien" was published in 1838 and contains the descriptions of 350 new species of recent molluscs, 26 of which are marine and freshwater bivalves from China and North America. Anton sold his vast collection in the 1850's to the Royal Cabinet of Natural History at Dresden (Königliches Naturalienkabinett zu Dresden) along with his handwritten catalogue. Due to unprofessional treatment of the collection before the First World War, the destruction and chaos during the Second World War and the fact that the malacological collection was not maintained for some decades afterwards, specialists have come to the over-hasty conclusion that the type material of Anton was lost forever. Fortunately, the handwritten and very detailed catalogue of the collections made by Anton himself is still available and it has enabled the current Collection Manager Katrin Schniebs to relocate a considerable part of the "lost" material. The bivalve type species have now been revised and the results are presented here to the scientific community. All specimen are now located in the Museum of Zoology collections of the State Collections of Natural History at Dresden (Staatliche Naturhistorische Sammlungen Dresden).

NEW TERMINOLOGY OF ROSTROCONCH MORPHOLOGY

Rogalla, N.S. and Amler, M.R.W.

(1*) State Collections of Natural History Dresden, Museum of Zoology, A. B. Meyer-Bau, Koenigsbruecker

Landstr. 159, D-01109 Dresden, Germany; rogalla@snsd.smwk.sachsen.de

(2) Institut für Geo- und Umweltwissenschaften, Sektion Palaeontologie, Ludwig-Maximilians-Universität,

Richard-Wagner-Str. 10, D-80333 Muenchen, Germany, concardium@web.de

It is always difficult to interpret the functional morphology of an extinct taxon due to the missing opportunity to study the life position and the position of internal organs in situ. The task is even more difficult, if these taxa lack extant descendants. Rostroconchs provide a good case in point. For more than 150 years since the first valid description of a species in 1815, this group was thought to belong to the class Bivalvia; today it is regarded as a proper class. The erroneous

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attribution to the Bivalvia, the wide geographic distribution of members of this class and possibly a lack of exchange between scientists in the 19th and early 20th century are probably the cause that the present terminology amounts to a babylonic mixture with many inaccurate and ill-defined terms in several languages. Even the publication of the first monograph (1) on the class Rostroconchia, which provided a careful definition, was partly ignored or insufficiently revised. Though it is not too difficult to correlate the different terms, even more recent descriptions use the same terms with different meanings. As a consequence, descriptions and definitions are no longer comparable - not even within the work of a single author. This situation significantly hampers determinations of material recently collected by colleagues and geology students as well as the badly needed revision of the class. We therefore present a revised and amplified terminology for the Ordovician to Permian "modern" rostroconchs (Conocariida) which adapts, as far as possible, the old terms and provides new definitions to old and new morphological features. Some features are newly interpreted to allow the use and comparability of descriptions at all taxonomic levels. This revised terminology has already been used in the latest revisions (2, 3) of the families Hippocardiidae and Pseudobigaleaidae.

(1) Pojeta J Jr and Runnegar B 1976, United States Geological Survey, Professional Paper, 968: 1-88.

(2) Rogalla NS and Amler MRW 2006, Paläontologische Zeitschrift, 80 (2): in press.

(3) Rogalla NS and Amler MRW 2006 Paläontologische Zeitschrift, 80 (3): accepted

MORPHOLOGY OF HIPPOCARDIID AND PSEUDOBIGALEAID (ROSTROCONCHIA)

LARVAL SHELLS AND THEIR SUBSEQUENT GROWTH

Rogalla, N.S. and Amler, M.R.W.

(1*) State Collections of Natural History Dresden, Museum of Zoology, A. B. Meyer-Bau, Koenigsbruecker

Landstr. 159, D-01109 Dresden, Germany; rogalla@snsd.smwk.sachsen.de

(2) Department fuer Geo- und Umweltwissenschaften, Sektion Palaeontologie, Ludwig-Maximilians-

Universitaet, Richard-Wagner-Str. 10, D-80333 Muenchen, Germany; concardium@web.de

In 1972 several authors (1) proposed the Class Rostroconchia (Mollusca) for a group of pseudobivalved fossils which had previously been

treated as crustaceans or aberrant bivalves. One of the group's most distinctive autapomorphic characters, apart from the connecting shell layers between left and right valve (2), is the univalved cap-shaped larval shell of these taxa (3). This feature gave rise to the idea that the Class Bivalvia was derived from rostroconch-like ancestors which thus acted as a link between the univalved and the bivalved morphologies. Based on the supposed rarity and poor preservation of larval shells, their usability and importance as a distinct and high ranking character on class level has often been ignored, although many more of them have subsequently been figured in new species and specimens (4). We here present exceptionally well preserved material of nine hippocardiid and pseudobigaleaid species, all of which show a previously undescribed and unique structure of the larval shell: it is always divided into a teardrop-shaped protoconch I and a posteriorly bilobed but nevertheless univalved protoconch II. Both larval stages are separated from each other or from the following juvenile dissoconch by a suture. The analysis of rarely found juvenile dissoconchs enabled us to reconstruct the change of growth directions in the transition from the protoconch II to the dissoconch. Compared to the shape of the adult shell, the larval shells cover the soft parts only dorsally and do not envelope the mollusc completely. Therefore, we suggest a change in life position between these ontogenetic stages. The nature of the larval shell of the so-called modern rostroconchs has already stimulated renewed discussions about two popular theories (Diasoma-Cyrtosoma concept versus Helcionelloida-Tergomya concept) concerning the phylogeny of the Phylum Mollusca (5). Here we present observations about this evolutionary conflict.

(1) Pojeta J Jr et al. 1972, Science, 177: 264-267. (2) Rogalla NS et al. 2003, Journal of Paleontology, 77

(4): 655-673. (3) Pojeta J Jr and Runnegar B 1976, United States

Geological Survey, Professional Paper, 968: 1-88. (4) Hoare RD et al. 2002, Paleontological Society

Memoir, 58: 1-30. (5) Peel JS 2004, Acta Palaeontologica Polonica, 49

(4): 543-550.

EXPANSION OF THE GENERIC DIVERSITY OF BIVALVES DURING THE TRIASSIC (I): SOME COMMENTS ON BIASES OF THEIR

RECORD

Ros, S. and De Renzi, M.

Institut Cavanilles, Universitat de València. Apartado Oficial 22085. Valencia E-46071, Spain

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Estimates of rates of origination and extinction may be biased by differential preservation of biominerals, area of outcrop or rarefaction (1). The Phanerozoic record of bivalves shows a clear bias for mineralogy and rarefaction (2, 3). We analyze some of these features related with the new genera arising during the Triassic. The Early Triassic as well as the Late Triassic is mainly characterized by materials formed in continental areas, whereas the Middle Triassic is basically made up of marine deposits. This may mean an important bias for the assessment of the marine fossil record of this period (4). We are going to test two hypotheses: (i) low surface of marine outcrops will bias the record of marine bivalves and (ii) mode of life (epifaunal and infaunal) influences preservation. Hypothesis (i) is tested by an indirect way. Genera of a small area of distribution survive shorter intervals of time than those of large area (duration would be a proxy of area) and thus, it is less probable to find them in function of a more restricted surface of marine outcrops. As in our previous papers (see above), we use the analysis of contingency tables technique jointly with the study of adjusted residuals. Data about origin of new genera during the Triassic as well as their duration come from (5). Mode of life has been obtained from available literature. Our sample consists of 157 genera.

We conclude that during the Early Triassic, long-living genera have significant presence, as we expected (marine deposits of this epoch show low surface of outcrop and thus, the record is biased in favouring genera of broad distribution). The distribution of modes of life throughout the Triassic period requires for its interpretation both preservational and evolutionary features.

(1) De Renzi M 1992, Conferencias de la Reunión de Tafonomía y Fosilización (Fernández López S, ed.): 63-85, Editorial Complutense, Madrid.

(2) De Renzi M & Ros S 2002, Current topics on taphonomy and fossilization (De Renzi M et al., eds.): 77-88, Col·lecció Encontres, Valencia.

(3) Ros S & De Renzi M 2005, Ameghiniana 42: 549-558.

(4) Márquez-Aliaga A & De Renzi M 1990, Comunicaciones de la Reunión de Tafonomía y Fosilización (Fernández López S, ed.): 179-193, Editorial Complutense, Madrid.

(5) Sepkoski J.J.,Jr. 2002, Bulletins of American Paleontology 363: 560 pp

BIVALVES ASSOCIATED WITH ZOSTERA MARINA BEDS IN SOUTHERN SPAIN

Rueda, J.L., Urra, J., Salas, C., and Gofas, S.

Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, Málaga 29071, España; (1*) jlruedaruiz@yahoo.es

In southern Spain, extensive seagrass beds of Zostera marina occur on the Mediterranean coasts at 8-17 meters depth, which are probably the deepest located within Europe. The composition and dynamics of the bivalve assemblages (epifaunal and infaunal species) associated with these Z. marina beds have been studied at 12-14 meters depth in two different sampling surveys. The first survey focussed on the epifaunal species which were sampled monthly with a small Agassiz trawl (sampled area ~ 222 m2) from March 2000 to March 2001. During the second survey, focussed on the infaunal species, 5-6 samples were taken in each season from spring 2004 to winter 2005 (total sampled area per season ~ 0,31 m2) using scuba diving equipment. A total of 3547 bivalves were examined with 1492 and 2055 individuals collected during the first and second survey, respectively.

A total of 54 species, 13 epifaunal and 41 infaunal are associated with these seagrass beds. The families Veneridae (8 sp.) and Tellinidae (7 sp.) dominated in terms of number of species. In terms of abundance, epifaunal bivalves such as Mytilidae and Anomiidae dominated in comparison with infaunal species in the first survey. In the second, infaunal, survey, the families Tellinidae and Veneridae were dominant. The dominant bivalves in Z. marina beds are infaunal such as Tellina distorta, Dosinia lupinus, Tellina fabula and Chamelea gallina. The top dominant epifaunal bivalves were filter feeders such as Anomia ephippium, Musculus subpictus and Musculus costulatus. The temporal dynamics of the bivalve taxocoenosis associated with Z. marina beds displays a seasonal trend in species richness with high values during summer. Abundance dynamics are also seasonal, with high values for the epifaunal bivalves during summer and for infaunal bivalves in autumn. Multivariate analyses performed with fourth root transformed abundance data displayed also significant seasonal patterns. These seasonal changes are probably linked with the annual variation of these Z. marina beds such as seagrass complexity (e.g. shoot density, biomass, etc..) for epifaunal species and sediment characteristics (e.g. percentage of organic matter) for infaunal species.

PHYLOGENETICS OF PECTEN SCALLOPS BASED ON 3 MITOCHONDRIAL GENES

Saavedra, C. and Peña, J.

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(1*, 2) Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas, Ribera

de Cabanes, 12595 Castellón, Spain; (1*) saavedra@iats.csic.es

Scallops of the genus Pecten are conspicuous members of the Family Pectinidae that live in sandy bottoms around European, African and Australasian coasts. In a previous study, we showed that the southern Australasian species P. fumatus and P. novaezelandiae, from Australia and New Zealand, respectively, were clearly separated form Atlantic P. maximus and Mediterranean P. jacobaeus, based on sequences of the 16S rRNA gene. However, divergence between the Atlantic/Mediterranean clade and the southern Australasian clade was too small to fit the accepted model of separation at the time of the Tethys Sea closure (ca. 15 million years b.p.). We propose that a model based on Vermeij's hypothesis of pre-Pleistocene transequatorial dispersal from Europe to South Africa (1), and Beu and Darragh's hypothesis of subsequent transportation to Australia and New Zealand by the Circum-Antarctic current (2) could be in the origin of the southern Australasian taxa. This Beu-Darragh-Vermeij model predicts that the South African species P. sulcicostatus should show an intermediate position in phylogenetic trees. We have tested this prediction by partially sequencing three mitocondrial genes (16S ,12S rRNA, COI) in the whole set of taxa.

(1) Vermeij, G.1992. Mar. Biol. 112: 343-348. (2) Beu, A. and Darragh, T.A., 2001. Revision of

southern Australian Cenozoic fossil Pectinidae (Mollusca: Bivalvia). Proc. R. Soc. Victoria 113: 1-205.

GENOMIC TOOLS FOR POPULATION BIOLOGY STUDIES IN CLAMS AND

SCALLOPS

Saavedra, C., Cordero, D., and Peña, J.B.

(1*, 2, 3) Instituto de Acuicultura de Torre la Sal, Consejo Superior de Investigaciones Científicas, 12595

Ribera de Cabanes, Castellón, Spain; (1*) saavedra@iats.csic.es

Genomics is changing the way in which biological research is being performed. The interface between genetics and population biology, which crystalized during the 20th century in the fields of population genetics, quantitative genetics and phylogenetics, is now provided with whole genome sequences, genomic libraries, linkage maps and microarrays. We are

presently using available EST collections obtained from cDNA libraries to develop large amounts of molecular markers in two groups of bivalves. These ESTs contain abundant information on potentially polymorphic DNA regions, such as microsatellites and introns, and on single nucleotide polymorphic sites. The markers will be used to study the genetic structure of populations, to construct linkage maps and to perform statistical genomic studies of life history traits.

THE PERIOSTRACUM OF DIGITARIA DIGITARIA (BIVALVIA: ASTARTIDAE):

FORMATION AND STRUCTURE

Salas, C., Pablo, M., and Checa, A.G.

(1*, 2) Depto. Biología Animal, Facultad de Ciencias, Universidad de Málaga, 29071-Málaga, Spain;

(1)casanova@uma.es. (3) Depto. Estratigrafía y Paleontología, Facultad de Ciencias, Universidad de Granada, 18071-Granada,

Spain; acheca@ugr.es

Digitaria digitaria (Linné) is a small Astartidae from North Atlantic waters, the shells of which are characteristic because of the presence of oblique ribs. The present study is part of a research programme on the process of calcification in bivalves, within which we studied the formation, structure and growth of the periostracum of D. digitaria. The periostracum is originated by the basal cells, located at the bottom of the periostracal groove. It is secreted in the intercellular space between the basal cell and the first cell of the outer fold, and in this point it seems to be structured in three layers: fibrous, membranous and dark homogeneous. Along the periostracal groove, the periostracum grows adhered to the outer epithelial cells of the middle fold. Electron and scanning microscopy observations reveal that epithelial cells of both outer and middle folds are implied in the formation of the periostracum. The first cell of the outer fold lacks microvilli, but the other epithelial cells present microvilli, being responsible of the secretion of the fourth (translucent) layer. The epithelial cells of the middle fold present many inclusions that scanning microscopy has revealed are secreted as fibrils throughout glandular openings. The fibrils forms a layer (fibrous) which is more or less uniformly pitted when recently formed, whereas the pits later become filled in. The microvilli of the epithelial cells from the outer fold show a linear border, while the microvilli of the epithelial cells of the middle fold show an undulating

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figure. Because of this, the periostracum of D. digitaria also develops an undulating form.

EARLY ORDOVICIAN BIVALVE RADIATION IN THE NORTHWESTERN AND

FAMATINA BASINS OF ARGENTINA

Sánchez, T.M.

CIPAL, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba. Av. Velez

Sársfield 299. X5000JJC Córdoba, Argentina; tsanchez@com.uncor.edu

The Ordovician (490-443 My) diversification is marked by an increase of both marine diversity and ecospace occupation in most of invertebrate groups. Bivalves underwent a remarkable diversification in the Early Ordovician basins of western Argentina, showing a notable combination of morphologic as well as ecological innovations. The fauna includes some genera that could be considered as the basal stages of lineages leading to cycloconchids, anomalodesmatans, and probably glyptarcoids in the Tremadoc (485- 480 My), and to the arcoids in the middle Arenig. The Northwestern Argentina basin (NWA) comprises six families and nine genera of Tremadoc age, and nine families and eleven genera of Arenig age (480-470 My). Middle Arenig strata of the Famatina basin have yielded seven families and seven genera.

From a paleoecological perspective, one can observe the colonization of low-saline waters in middle Arenig-Llanvirn (473-460 My) strata of the NWA. On the basis of taxonomy, mode of life, and feeding types thirteen guilds were recognized. In the NWA assemblages, six guilds were occupied during the Tremadoc and eight during the Arenig whereas in the Famatina basin six guilds were occupied in the mid-Arenig. Life styles include free endofaunal, semi-endofaunal, semi-endobyssate, and epibyssate; feeding types include suspensivorous and detritivorous habits. Recent discoveries of Tremadoc and early Arenig bivalves from the NWA show that dominance of higher groups (e.g. Heteroconchia, Pteriomorphia) deviates from patterns based on other Gondwanan faunas. This agrees with previous ideas supporting the importance of local radiations in the Ordovician diversification.

ARMOURED SIPHONS IN LATERNULIDS (ANOMALODESMATA)

Sartori, A.F.

Department of Earth Sciences. University of Cambridge. Downing Street, Cambridge. CB2 3EQ. U.

K.; andrefsartori@yahoo.com.br

The mantle margins of several anomalodesmatan bivalves bear multicellular glands whose mucoid secretion attaches sediment particles to the outer surface of the periostracum. These organs, termed arenophilic radial mantle glands, are the only morphological feature that is exclusive of anomalodesmatans(1) and have thus been used as a key character in recent attempts to unravel the evolutionary relationships within the group(2). Nevertheless, arenophilic glands are not present in all anomalodesmatans, having not been hitherto reported in laternulids, despite the dense cover of extraneous material found on the siphons of most species of the family(3). As part of an ongoing investigation on the biology of laternulids, the functional morphology of the mantle and siphons of Laternula elliptica (King & Broderip, 1831), L. truncata (Lamarck, 1818), L. boschasina (Valenciennes in Reeve, 1864) and L. marilina (Valenciennes in Reeve, 1864) were studied by dissections, serial histological sections and scanning electron microscopy. It was found that arenophilic glands occur in all four species, laying down their secretion as threads organized in longitudinal lines along the whole length of the periostracum that covers the siphonal walls. While they were confined to the siphonal tips in adult individuals of all investigated species, two vestigial arenophilic glands were discovered within the limits of the pedal aperture of a juvenile of L. elliptica (1.7 cm in shell length). These observations suggest that in laternulids the glands that line the general mantle margin are lost during ontogeny, the only remaining ones being those of the siphonal tips. Conditions in the Laternulidae are thus probably derived from that seen in most anomalodesmatans, in which the glands are more or less evenly distributed along the whole extent of the mantle margins. [Study financially supported by: Gates Cambridge Trust, ORSAS, Emmanuel College, Malacological Society of London.]

(1) Prezant RS 1998, In: Beesley PL et al. (eds), Mollusca: The Southern Syntesis, Fauna of Australia 5, Part A, pp. 397-429. CSIRO Publishing, Melbourne.

(2) Harper EM et al. 2000, In: Harper EM et al. (eds), The Evolutionary Biology of the Bivalvia. Geological Society, special publications 177: 129-143.

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(3) Morton B 1973, Bulletin of the Marine Biological Laboratory, Woods Hole, 145: 509-531.

GREAT DIVERSITY IN SMALL SPACE - A REMARKABLE BIVALVE ASSOCIATION

FROM THE LOWER PLIOCENE OF HAROKOPIO (SW PELOPONNESUS,

GREECE)

Schneider, S. and Hochleitner, R.

(1*) Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Str. 10, D-80333 München,

Germany; cuspidaria@web.de (2) Mineralogische Staatssammlung München, Theresienstr. 41, D-80333 München, Germany

Fossiliferous sediments from the Pliocene are widespread on the Peloponnesus. Due to tectonic activities, a rich pattern of marine, brackish, and freshwater habitats developed in this area during the Pliocene. We here present an excellently preserved and highly diverse marine bivalve association from the coastal section of Harokopio (SW Peloponnesus). The locality yields an autochthonous soft-bottom fauna, partly preserved in situ in a several-decimeter thick layer of sands and marls. The sediments are dated as MNN 14 based on calcareous nannoplankton and belong to the MPMU 1 (Mediterranean Pliocene Molluscan Unit) Bivalves larger than 1 cm were picked in the field and approximately 5 kg of sediment were wet-sieved to obtain smaller shells. Dried residues were picked down to 0.5 mm.

A total of 82 species, 65 genera, and 28 families were discovered. This is one of the richest bivalve faunas recorded from the Greek Pliocene to date. The mollusc association, as well as the accompanying foraminifers and ostracods, are indicative of a well-oxygenated shallow water habitat. The small scale lateral change of sediment grain size, visible in the section, provided a variety of niches occupied by e.g., five co-occurring Acanthocardia species and 15 venerid species. The most outstanding feature is the great diversity of small heterodonts, belonging to the Galeommatidae, Kelliidae, Leptonidae, and Montacutidae. These taxa are represented by none less than 11 species. Several extant representatives of these groups are known to live as commensals on echinoderms, sipunculids or polychaets, and their presence in the fossil record permits conclusions on the existence of those rarely preserved organisms. This may help to more fully depict the ecosystem. In addition, the first record for the Aegean

region of several species provides new information on Pliocene palaeobiogeographic patterns.

ONTOGENETIC VARIATIONS OF THE EARLY CRETACEOUS NON-MARINE

BIVALVE TRIGONIOIDES (T.) HEILONGJIANGENSIS AND THEIR PHYLOGENETIC SIGNIFICANCE

Sha, J.

Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road,

Nanjing, 210008, China; jgsha@nigpas.ac.cn

Trigonioides is a typical genus of Trigonioidoidea with the anterior pedal retractor scar distinctly separated from anterior adductor scar, and distinctive ribbing (1, 2). Trigonioidids were widely distributed in Asia, as well as parts of Europe such as southern England during the Cretaceous (3). However, there is no agreement on the origin of these special bivalves, either from marine Trigoniiidae or from freshwater Unionidae (1, 2, 4). There exist a series of well-preserved specimens, representing various growth stages, of Trigonioides (T.) heilongjiangensis in the Lower Cretaceous Xiachengzi Formation of northeastern China (1, 2). With growth, both the strength of hinge crenulation and the number of submedian teeth of the species increase; the angle of V-shaped ribs (VA) on the median flank of the species enlarges and the secondary radial ribs on the anterior half vary from simple, but prominent, through feeble or vanished to bifurcate or multiple and clear. During the early growth stage (< 20 mm), hinge teeth are smooth in individuals less than 10 mm long and feebly crenulated shells 10 to 20 mm long; shells are entirely sculptured with radial, second-order ribs and VA is commonly ca. 10-12º. The next larger growth stage (20 to 40 mm in length), has distinct crenulations whereas the second-order ribs, particularly those on the anterior half, are either lost (more common) or they may be subdivided into numerous faint threads and obscured by growth lines. A submedian tooth does not occur until the adult stage longer than 40 mm, when shells are again covered with second-order, radial ribs and VA is commonly 20-25º. Adult shells larger than 55 mm in length can have up to 4 submedian teeth in the right valve and 3 in the left valve (1, 2). These ontogenetic variations of T. (T.) heilongjiangensis have clarified the evolutionary trends and suggest that trigonoidids arose from unionids.

(1) Sha JG 1992, Paläontologische Zeitschrift 66: 241-264.

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(2) Sha JG et al. 1993, Beringeria 8: 139-187. (3) Sha JG 2006, Journal of Asian Earth Sciences (in

press). (4) Sha JG 1993, Acta Palaeontologica Sinica 32: 285-

302.

ANATOMY AND FUNCTIONAL MORPHOLOGY OF THE SOUTHWESTERN

ATLANTIC BIVALVE MACTRA ISABELLEANA D'ORBIGNY, 1846 (HETERODONTA: MACTRIDAE)

Signorelli, J.H. and Pastorino, G.

Museo Argentino de Ciencias Naturales, Av. Angel Gallardo 470, C1405DJR. Buenos Aires, Argentina;

jsignorelli@macn.gov.ar

The main objective of this project is the study of the functional morphology of Mactra isabelleana. This sandy-bottom bivalve is one of the most frequent along the coast of Buenos Aires province. It occurs from Rio de Janeiro, Brazil to Golfo San Matías, Argentina (1). Its anatomy is described using a stereoscopic microscope and traditional histology.

A trigonal shell with growth lines over the entire surface and a thin and brownish periostracum are the main external features. The ultrastructure of the aragonitic shell consists of two layers; the outer, cross-lamellar (CL) layer is constituted of very thin lamellae; the inner layer is finer and with a complex CL structure. Two anterior and two posterior lateral teeth are present in the right valve hinge, which also has two V-shaped cardinal teeth. In the left valve hinge there are two lateral teeth; the posterior one and the anterior one with accessory lamellae, and two V-shape cardinal teeth with accessory lamellae flanking the chondrophore. The umbo is orthogyrate and the external posterodorsal ligament is present. The digestive system and mantle cavity organs are illustrated and described to explain the food current. The siphons are of the type C of Yonge (2). The stomach is of the type V of Purchon (3). The ctenidia are connected at the posterior end, surrounding the body. Each ctenidium consists of a inner and outer demibranch with a supra-axial outer demibranch. They are apparently of the type C(2) of Atkins. The labial palps are triangular with the inner faces plicated and outer faces smooth and their relationship with the ctenidium belong in category III of Stasek. Preliminary anatomy of this species of Southwestern Atlantic Mactridae basically agrees with previous studies.

(1) Rios EC 1994, Seashells of Brazil, Editora da Fundaçao Universidade do Rio Grande, 368 pp.

(2) Yonge CM 1948, Nature 161: 198-199. (3) Purchon FLS 1960. Proc. Zool. Soc. London 135

(3): 431-489.

SEQUENCE ANALYSIS OF THE RIBOSOMAL GENE REPEATS OF SOME BIVALVE

SPECIES

Silva Hurtado, N., Morán, P., and Pasantes, J.J.

Dpto. Bioquímica, Xenética e Inmunoloxía, Facultade de Bioloxía, Universidade de Vigo, E - 36310 Vigo,

España; (1*) silva@uvigo.es

The eukaryotic DNA sequences that code for the major and 5S ribosomal RNAs (18+28S rDNA and 5S rDNA) are repeated in tandem. The repeats consist in highly conserved coding regions and non-conserved spacers. As happens in other tandemly repeated multigene families, major and 5S rDNA repeats experiment concerted evolution so the spacer regions of the repeats present a high degree of intra-specific sequence similarity but differ among species. The internal transcribed sequences (ITS) and the 5.8S coding region of the major ribosomal genes and the whole 5S rDNA repeat were PCR amplified in samples of nine species of bivalves belonging to the families Cardiidae (Cerastoderma edule ), Mactridae (Spisula solida), Donacidae (Donax trunculus), Veneridae (Venus verrucosa, Dosinia exoleta, Ruditapes decussatus, Ruditapes philippinarum and Venerupis pullastra) and Glycymerididae (Glycymeris glycymeris). Sequence analysis showed a high degree of variation of spacer sequences among species and conservation of the coding regions. The sequence similarity is higher in the 5S than in the 5.8S coding regions. ITS1 and ITS2 RNA structures were also compared.

GENETIC EVIDENCE OF NATURAL HYBRIDIZATION BETWEEN RUDITAPES

DECUSSATUS AND R. PHILLIPINARUM

Silva Hurtado, N., Morán, P., and Pasantes, J.J.

Dpto. Bioquímica, Xenética e Inmunoloxía, Facultade de Bioloxía, Universidade de Vigo, E-36310 Vigo,

España; (1*) silva@uvigo.es

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The grooved carpet shell, Ruditapes decussatus, and the Japanese carpet shell, Ruditapes philippinarum, are among the most common species of clams found in the market for human consumption. While R. decussatus has been collected and cultured along the Galician coast (NW Spain) for centuries, R. philippinarum has been introduced in Europe some few years ago due to its high growth rate and resistance. Samples of Ruditapes spp. were collected from Arcade, a locality on the Galician coast where the two species live together. Specimens were identified on the basis of morphological characters.

PCR amplification of the 5S rDNA showed that the sizes of the amplified fragments are different in R. decussatus (593 bp) and R. philippinarum (526 bp). In most specimens only one of the fragments was present but 9 individuals were hybrids and both kinds of fragments were amplified. Cloning and sequencing of the amplified fragments demonstrated that one of them matchs to the R. decussatus product and the other to the R. philippinarum one. A similar situation was detected by amplification of the internal transcribed spacers (ITS) of the major ribosomal RNA genes; the 9 hybrid individuals presented both R. decussatus and R. philippinarum products. Fluorescent in situ hybridization (FISH) of major and 5S rDNA sequences to surface spread synaptonemal complexes demonstrated that the chromosomal location of those sequences on the bivalents corresponds to both R. decussatus and R. philippinarum and further confirmed the existence of hybrid individuals. Because the PCR amplification of the mitochondrial 16S rDNA of the hybrids generated an amplification product identical to the one obtained in R. decussatus we conclude that the hybrids have R. decussatus mothers

PROPOSALS FOR A REVISED CLASSIFICATION OF RUDIST BIVALVES

Skelton, P.W.

Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA, UK; P.W.Skelton@open.ac.uk

The Treatise classification of rudists (1) was dated on appearance, even including polyphyletic families. Subsequent phylogenetic analysis (2) offers better scope for defining monophyletic taxa. Recognition of basal dichotomies within the rudist clade requires extension of their taxonomic hierarchy. Hence, I propose to elevate them from superfamily level (Hippuritoidea (2)) to that of order. In effect, this promotion rejects the (problematical) 'Megalodontoidea' from the Order

Hippuritoida Newell and restricts the latter taxon to the rudists. To avoid nomenclatural confusion, this order might - controversially - be renamed 'Rudista'; although type-based nomenclature is not mandatory above the family-group level (3), it is nevertheless conventional for bivalve orders. The most basal dichotomy separates rudists attaching by the right valve from those attaching by the left valve, yielding two superfamilies, the first retaining the name Hippuritoidea Gray, by priority, and the second here named Requienioidea Douvillé. Within the latter, only one monophyletic family is readily defined, Requieniidae Douvillé, leaving a paraphyletic residue of basal genera, 'Epidiceratidae'. Within the Hippuritoidea, a similar paraphyletic taxon, 'Diceratidae' accommodates the two basal genera that still retain an external ligament, Diceras and Valletia. All other hippuritoideans have an invaginated ligament, and can mostly be divided among monophyletic families (2). The latter include Caprinidae d'Orbigny, sensu stricto (4), though possibly now also excluding a separate Neocaprina/Caprinula clade (5), Plagioptychidae Douvillé, Hippuritidae Gray and Radiolitidae d'Orbigny. Outstanding problems include the affinities of certain small clades and a paraphyletic residue of uncoiled rudists in need of taxonomic homes.

(1) Dechaseaux C et al. 1969, In: Moore RC (ed.) Treatise on Invertebrate Paleontology, (N) Mollusca 6 Bivalvia, Geological Society of America and University of Kansas: N749-N817.

(2) Skelton PW & Smith AB 2000, In: Harper EM et al. (eds.), The evolutionary biology of the Bivalvia, Geological Society, Special Publication 177: 97-127.

(3) Ride WDL et al. (eds.) 1999, International Code of Zoological nomenclature. Fourth Edition. International Trust for Zoological nomenclature, C/O The Natural History Museum, London, UK. 306 pp.

(4) Skelton PW & Masse J-P 1998, Géobios, mémoire spécial, 22: 331-370.

(5) Steuber T & Bachmann M 2002, Palaeontology, 45: 725-749.

THE ASIAN CLAM CORBICULA FLUMINEA (MÜLLER, 1774) IN THE MINHO AND

LIMA ESTUARIES: GENETICS VS. MORPHOMETRY

Sousa, R., Freire, R., Méndez, J., Rufino, M., Gaspar, M., Antunes, C., and Guilhermino, L.

(1*, 6, 7) CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas

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289, 4050 Porto, Portugal; ronaldo.sousa@ciimar.up.pt .

(1, 7) ICBAS - Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Departamento de

Estudos de Populações, Laboratório de Ecotoxicologia, Lg Prof. Abel Salazar 2, 4099-003 Porto, Portugal. (2,

3) UDC - Departamento de Biologia Celular y Molecular, Facultad de Ciencias, Universidade da

Coruña, A Zapateira, La Coruña, Spain. (4, 5) INIAP/IPIMAR - Instituto Nacional de

Investigação Agrária e das Pescas, Centro Regional de Investigação Pesqueira do Sul (CRIPSul), Av. 5 de

Outubro, 8700-305 Olhão, Portugal. (6) Aquamuseu do Rio Minho - Parque do Castelinho,

4920-290 Vila Nova de Cerveira, Portugal.

Corbicula species are non-indigenous, invasive bivalves in aquatic ecosystems in Portugal with potentially negative environmental and economical impacts. Straight forward species identification within the genus is hampered, however, by their highly variable shell shape, colour and sculpture. We therefore analysed the diversity of individuals from the Minho and Lima estuaries, NW of Iberian Peninsula, employing (a) conventional morphometric measures (shell length, width and height), (b) geometric methods based on landmarks analysis (shell interior as well as contour using elliptic Fourier analysis) and (c) genetic analysis (mitochondrial cytochrome c oxidase subunit I gene sequence).

While landmark and contour analysis showed a clear separation between the individuals' shell shape from the two estuaries their mtCOI sequences were identical. We therefore conclude that the two estuaries have distinct populations of Corbicula fluminea.

DIFFERENT INVASIVE BEHAVIOUR OF THE NON-INDIGENOUS SPECIES CORBICULA

FLUMINEA (MÜLLER, 1774) IN TWO ADJACENT PORTUGUESE ESTUARINE

ECOSYSTEMS

Sousa, R., Antunes, C., and Guilhermino, L.

(1*, 2, 3) CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas

289, 4050 Porto, Portugal; ronaldo.sousa@ciimar.up.pt .

(1, 3) ICBAS - Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Departamento de

Estudos de Populações, Laboratório de Ecotoxicologia, Lg. Prof. Abel Salazar 2, 4099-003 Porto, Portugal.

(2) Aquamuseu do Rio Minho - Parque do Castelinho, 4920-290 Vila Nova de Cerveira, Portugal.

The species Corbicula fluminea, with origin in Asia, has been dispersing worldwide in the last 80 years. This non-indigenous species is one of the most invasive bivalves in aquatic ecosystems and recently colonized the Minho and Lima estuaries (NW of the Iberian Peninsula). Spatial and temporal variations in abundance, biomass and population structure of C. fluminea were investigated in the Minho (16 sampling stations) and Lima (9 sampling stations) estuaries.

In the Minho estuary the species was introduced at least in 1989 and nowadays has great abundances and biomasses. Annual surveys performed in 2004 and 2005 registered a mean abundance and biomass of 1100 ind./m² and 97 g AFDW/m², respectively. In the Lima estuary, C. fluminea was registered for the first time in 2002 and still has very low abundances and biomasses. In 2004 and 2005, mean abundances and biomasses were 13 ind./m² and 8 g AFDW/m², respectively. Some exploratory hypotheses (e. g. different abiotic conditions, different propagule pressure and/or genetic differences) that could contribute to the different invasive behaviour of the species in the Minho and Lima estuaries are discussed.

ONTOGENY OF CILIATION OF VELUM RIM AND MANTLE FOLDS IN VELIGER LARVAE

OF CRASSOSTREA GIGAS

Stanton, S.A.

University of Portsmouth, School of Biological Sciences, Institute of Marine Sciences, Ferry Road,

Eastney, Portsmouth, Hants, P04 9LY; sam.stanton@port.ac.uk

Scanning electron microscopy and light microscopy, including confocal laser scanning microscopy (CLSM) were used to examine the ciliation of the mantle folds and velar rim of Crassostrea gigas larvae. Fracturing specimens with glass needles revealed complex and ordered cilia groupings on the mantle folds. Discrete cilia groups were characterised and mapped at stages in larval ontogeny. Some larvae were partially sectioned in wax before being dissolved out and mounted for SEM viewing.

Ciliation of the mantle rim shows an increase in complexity with development. Pediveligers have dense tracts of cilia on the inner mantle fold running from the gill around the ventral region. These tracts have been

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observed beating in live specimens. Groups of cilia with associated stereocilia occur in the region abutting the gill bud and on the posterior mantle rim. These stereocilia have a corona of nine microvilli and are comparable to the collar receptors identified in adult Nucula (1). Additional mantle cilia groupings bear some comparison to those identified in Pecten larvae (2) and in Ostrea edulis (3). A previously unrecorded row of compound cilia was identified on the velar rim below the main preoral cilia. Fluorescence associated with catecholamines was localized using CLSM in areas such as the velar rim and mantle. Croll et al. (4) have previously reported catecholamines in the mantle and velum of larval bivalves.

(1) Haszprunar G, 1985, The Veliger, 28(1), 52-62. (2) Cragg, SM, 2006, In: Scallops: Biology, Ecology

and Aquaculture (SE Shumway & GJ Parsons eds.), pp 45-122. Elsevier.

(3) Waller T R, 1981, Smithsonian Contibutions to Zoology, 328: 1-70.

(4) Croll et al, 1997, Biological Bulletin, 193: 116-124.

WHAT CAN MITOCHONDRIAL GENOMICS DO FOR BIVALVE PHYLOGENY?

Steiner, G., Dreyer, H., and Knapp, M.

Molecular Phylogenetics, Dept. Evolutionary Biology, Univ. Vienna, Althanstr. 14, A-1090 Vienna, Austria;

gerhard.steiner@univie.ac.at

Molecular phylogenetics of Bivalvia mainly inferred from nuclear ribosomal and COI sequences, though yielding some valuable results, has not resolved important questions like, e.g., the relationships of the major taxa. Complete mitochondrial genome sequences are valuable sources for phylogenetic signal providing both nucleotide and genomic data, i.e. gene content and gene order. Contrasting vertebrates and arthropods, molluscan mitochondrial gene order varies considerably, especially within the Bivalvia. We present phylogenetic analyses of complete mitochondrial genomes of 18 bivalve and 16 other molluscan species.

The gene order in Bivalvia is highly heterogeneous. Even closely related species show several rearrangements, and none except for Nucula, the single protobranch representative, resembles the putative plesiomorphic condition in molluscs. With the Nucula gene order differing by only two rearrangements from that of the polyplacophoran Katharina, the high rearrangement rates must have arisen within Bivalvia. Consequently, phylogenetic inference using gene order data with the present taxon sample and analysis methods

yield unreliable results. Maximum likelihood and Bayesian inference of nucleotide and amino acid data yield robust Autobranchia, Pteriomorpha, and Heterodonta. Bivalve monophyly is not supported as Nucula clusters with Haliotis and Katharina at the base of the tree. This notable similarity of gene order and sequence trees suggests a rate correlation of nucleotide substitutions and gene rearrangements. Given these initial results, what can mitochondrial genomics do for bivalve phylogeny? The trees based on the combined sequences of the protein coding genes yield much better results than studies using COI alone and match those based on 18S rRNA and morphology data. Especially within the Heterodonta the resolution is likely to be superior to all other available data sets. Little hope remains, however, that gene order data will resolve the sistergroup of bivalves. Improving both the taxon sampling and analysis methods will show the taxonomic level - or time window - gene order data contain robust phylogenetic signal. With a growing number of complete genomes, in particular that of closely related species, additional genomic characters, such as gene duplication and loss, rearrangement hotspots, and occurrence of doubly uniparental inheritance, are likely to be assessed.

NUCLEOTIDE SUBSTITUTION STRAND BIAS AND CONTROL REGION ORIENTATION IN

BIVALVE MITOCHONDRIAL GENOMES

Steiner, G., Dreyer, H., and Knapp, M.

Molecular Phylogenetics, Dept. Evolutionary Biology, Univ. Vienna, Althanstr. 14, A-1090 Vienna, Austria;

gerhard.steiner@univie.ac.at

The frequency of different types of nucleotide substitutions in mitochondrial genes differs according to the strand the genes is encoded on. As a result, the genes on the so-called light strand (L) are rich in A and C and have positive AT and CG skews; those encoded on the heavy strand (H) are rich in T and G and have negative AT and CG skews. This is best seen in the weakly selected third codon positions. The mechanism considered responsible for this bias is the asymmetric replication process of the mitochondrial genome due to the asymmetry of the origin of replication or control region. The L-strand contains the "preferred side" of the control region and is replicated more rapidly than the H-strand. By comparing the CG-skews of protein coding mt-genes changes of the orientation, inversions, of the control region can be assessed for species having identical gene order or having all genes on the same

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strand. We compared the protein coding mt-genes of 18 bivalve species to those of other molluscs, annelids, and a brachiopod. All but three species of bivalves have all genes encoded on the same strand. Only the two unionids and Nucula nucleus have four and three genes, respectively, encoded on the other strand. We conclude from gene order, CG-skew data, and phylogenetic relationships, that at least two inversions concerning the control region occurred in the evolution of the Mollusca. One occurred most likely along the branch leading to the polyplacophoran Katharina and the other along the branch of the autobranch bivalves. The incorporation of the strand-specific substitution biases into likelihood models used for phylogenetic inference may considerably improve their performance and reliability.

RELATIONSHIPS OF HETERODONT BIVALVES: NEW MOLECULAR DATA FOR

46 FAMILIES. OUT WITH THE OLD IN WITH THE NEW?

Taylor, J., Williams, S., Glover, E., and Dyal, P.

(1*, 2-4) Department of Zoology, The Natural History Museum, London SW7 5BD, United Kingdom

This study includes new long sequences of 18S rRNA and 28S rRNA genes for 97 species representing 46 family groups of heterodont bivalves. Several families such as Gaimardiidae, Trapeziidae and Hemidonacidae are included in molecular analysis for the first time. The objectives were to determine the relationships of the major groups of heterodont bivalves but with particular reference to the positions of the Thyasiridae, Lucinidae and Ungulinidae, previously included in the Lucinoidea. The analysis identified a number of well-supported major clades but relationships between these were less robust. Some major superfamilies such as Tellinoidea, Mactroidea and Cardioidea are confirmed as monophyletic but the Myoidea, Corbiculoidea and Lucinoidea are paraphyletic groups. Results confirm the position of the Carditidae/Astartidae/Crassatellidae clade followed by Thyasiridae as basal to all other heterodonts including the Anomalodesmata, while the Ungulinidae nest near the Veneridae, Arcticidae, and Mactridae. Implications of these and other molecular results for the classification of the heterodonts will be discussed.

OVERCOMING INCONGRUENCE IN THE PHYLOGENY OF THE PTERIOIDEA

Tëmkin, I.

American Museum of Natural History, Division of Invertebrate Zoology, 79th street at Central Park West,

New York, New York, 10024, USA

The marine bivalve superfamily Pterioidea is a morphologically exceptionally diverse group with a fossil record extending to the lower Middle Ordovician (pterineid Denticelox) (1). Throughout the Phanerozoic, the pterioideans have occupied a remarkable variety of epifaunal habitats in tropical and subtropical continental shelf regions around the globe and have been integral components of virtually every benthic ecosystem. However, little is known about the relationships within the Pterioidea and understanding of evolution of the group is in its infancy. The phylogenetic analyses of the Recent Pterioidea based on morphology and DNA sequence data agree on the monophyly of the superfamily and its genera, and the non-monophyly of all families (except the Pulvinitidae). However, they differ considerably with regard to deep (Triassic and Jurassic) lineage-splitting events. Possible causes of idiosyncratic behavior of different partitions will be addressed and the new phylogeny for the crown-group (post-Paleozoic) Pterioidea will be proposed based on the results of new cladistic analysis and stratigraphic considerations. The controversial evolution of the ligamental systems in the Pterioidea will be considered in light of new findings and the proposed phylogeny.

(1) Pojeta and Runnegar 1985. In, Trueman and Clark (eds), Evolution. Academic Press, Orlando: 295-336.

ARCA ZEBRA (SWAINSON, 1833) (BIVALVIA: ARCOIDA): AN ECOLOGICAL ISLAND FOR POLYCHAETE COMMUNITIES

Vanegas-Espinosa, V., Díaz-Díaz, O., and Liñero-Arana, I.

Departamento de Biología Marina, Instituto Oceanográfico de Venezuela, Universidad de Oriente;

(1*) ecobentos12@hotmail.com; (3) ilineroarana@yahoo.es

The ark shell Arca zebra is a bivalve mollusc of commercial importance with a high socioeconomic impact in northeastern Venezuela (1) where its main population is located in Chacopata. The present study is

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part of a project which examines the polychaete communities associated with bivalves of commercial interest. Samples were collected in Chacopata (10º42´30´´N-63º48´30´´W) from October 2005 to January 2006 using a trawlnet. Samples were hold in plastic containers with sea water and ice and transported to the laboratory where the polychaetes were removed and fixed in formaldehyde 8%.

One thousand and seventy nine bivalves and 1279 polychaetes were examined. Forty-two polychaete species were identified belonging to 18 families. Eunicidae and Serpulidae were the best represented families in species richness as well as abundance. Typosyllis lutea (9.3%), Podarke obscura (8.3%), Lysidice ninnetta (7.8%) and Schistomeringos cf. rudolphi (7.5%) were the most abundant species. Previous work carried out in northeastern Venezuela (2, 3, 4) already revealed that the species richness associated with A. zebra is greater than the recorded species associated with Perna viridis, Pinctada imbricata, Isognomon alatus and Spondylus americanus; and it is only slightly inferior to the number of species associated with Crassostrea rhizophorae.

(1) Arias de Díaz A, Guzmán R et al. 2002. Zootécnica Tropical 20 (1): 46-67.

(2) Díaz-Díaz O., Liñero-Arana I. 2003. Interciencia 28(5): 298-301.

(3) Díaz-Díaz, O., Liñero-Arana I. 2003. Iberus 21(2): 61-65.

(4) Liñero-Arana I. 1999. Bol. Inst. Oceanogr. Venezuela, Univ. Oriente 38(2): 53-61.

OYSTER HERPESVIRUS IN CRASSOSTREA GIGAS CULTURED IN MEXICO

Vásquez-Yeomans, R., Cáceres-Martínez, J., and García-Ortega, A.M.

(1) Instituto de Sanidad Acuícola, A.C. Calle novena y Gastélum 468, 13-14. CP. 22800 Ensenada B. C.

México; (2*) Laboratorio de Biología y Patología de

Organismos Acuáticos, Departamento de Acuicultura, Centro de Investigación Científica y de Educación

Superior de Ensenada. AP. 2732, CP. 22800 Ensenada B. C. México; (3) Comité Estatal de Sanidad Vegetal de

Baja California. Km. 1.5 Carretera a San Felipe, Ex-Ejido Xochimilco, CP. 22310, Mexicali, B. C. México

Since 1997, high mortality episodes of cultured oysters have occurred in Bahía Falsa, México. Studies on the possible association of these mortalities with pathogens

have showed some similar characteristics to those found in the Portuguese oyster Crassostrea angulata and the Japanese oyster Crassostrea gigas infected by an iridoviridae-like particles in the late 60s in Europe. This infection was named gill necroses virus infection (GNV). In a recent study, we could not find any virus using transmission electron microscopy (TEM) in adult oysters with clinical and histological signs similar to those described for GNV. However, new TEM images showed the presence of viral particles in eroded gills of oysters. Morphological characteristics, such as thin-walled icosahedric shape, the presence of capsids in an extension of the nucleus or in a vacuole and size varying from 80 to 90 nm suggest that the viruses belong to the Herpesviridae family. Molecular analysis using primers C2 and C6 (1) confirm that those viral particles correspond to a Herpesvirus. Current studies are conducting to sequence this virus to determine whether it is the oyster herpesvirus OsHV-1 recorded in France and on the West Coast of the United States causing mortalities in juvenile oysters.

(1) Renault T et al. 2000, Journal of Virological Methods 88: 41-50.

ISOLATION AND IDENTIFICATION OF BACTERIA ASSOCIATED TO MORTALITY

EVENTS IN CRASSOSTREA GIGAS IN MEXICO

Vásquez-Yeomans, R., Cáceres-Martínez, J., and García-Ortega, A.M.

(1) Instituto de Sanidad Acuícola, A.C. Calle novena y Gastélum 468, 13-14. CP. 22800 Ensenada B. C.

México; (2*) Laboratorio de Biología y Patología de

Organismos Acuáticos, Departamento de Acuicultura, Centro de Investigación Científica y de Educación

Superior de Ensenada. AP. 2732, CP. 22800 Ensenada B. C. México; (3) Comité Estatal de Sanidad Vegetal de

Baja California. Km. 1.5 Carretera a San Felipe, Ex-Ejido Xochimilco, CP. 22310, Mexicali, B. C. México

Since the late 70s, the Japanese oyster, Crassostrea gigas, has been cultured in Bahía Falsa, Baja California, México. At present, there are 21 culture companies involved in this activity. In 1998, unusual mortality episodes of oysters began to occur, reaching up to 80% of the production. These mortality episodes have been recurred up to date and, the hypothesis of a possible pathogen involved, such as a virus, bacteria or both, remains open. This work shows the results of a study on the physiological and biochemical characterization of

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isolated bacteria from gill tissue of oysters recollected during a mortality episode in 2001. Three colonies were isolated, two of them grew in TCBS selective medium, forming yellow colonies, which were identified as belonging to the genus Aeromonas. The third colony could not be cultured or identified. There are not records on the pathogenicity of Aeromonas spp. in mollusks; however, they have been reported as pathogenic for fishes and reptiles. Identification of the no cultivable bacteria must be carry out by molecular methods

MOLLUSCS IN ARCTIC GLACIAL FJORDS - PATTERNS OF DISTRIBUTION AND DIVERSITY SHAPED BY GLACIAL

SEDIMENTATION

Wlodarska, M.

Institute of Oceanology PAS, Powstancow Warszawy 55, 81-712 Sopot, Poland; maria@iopan.gda.pl

Glacial activity (particularly the inflow of glacial melt-water loaded with mineral solids) is responsible for main environmental gradients in arctic glacial fjords. The marine biota of near-glacier marine basins must cope with high turbidity, high rate of inorganic particulate sedimentation and sedimentary instability. The chronic physical disturbance of sediments is accompanied by low input levels of organic matter. Response of soft-bottom molluscs to glacial disturbance was studied in Kongsfjord (Svalbard). 80 van Veen grabs were collected at 30 stations situated throughout the fjord (at depths from 38 to 380 m). Two mollusc associations located in glacial bays (high mineral sedimentation, instable sediments, ice-berg scouring) and three associations in the fjord's central basin (stable sediments not influenced by glaciers) were distinguished based on non-metric Multidimensional Scaling of Bray-Curtis similarities of species abundances in samples.

Molluscs coped surprisingly well with glacial sedimentation and were much more abundant in glacial bays (200-300 ind./0.1 m^2 ) than in central-basin assemblages (30-40 ind./0.1 m^2). The glacial bays associations were dominated by protobranch bivalves (Yoldiella solidula, Yoldiella lenticula, Yoldia hyperborea) and thyasirids (Thyasira dunbari, Thyasira gouldi, Axinopsida orbiculata). In central-basin associations yoldiids and thyasirids were much less abundant which may be due to competition with dense populations of deposit feeding tube-dwelling polychaetes. Significant clines of evenness (Pielou

index) and taxonomic distinctness of molluscs were recorded in near-glacier areas. However, glacial disturbance had no effect on soft-bottom molluscan species richness (number of species per sample) or species diversity (Shannon-Wiener index).

ALATOFORM EDGEWISE RECLINING BIVALVES APPEAR EARLY IN THE

TRIASSIC

Yancey, T. and Wilson, M.

(1*) Department of Geology & Geophysics, Texas A&M University, 3115 TAMU, College Station, Texas 77843-

3115, USA; tyancey@tamu.edu (2) Dept. of Geology, The College of Wooster, Wooster,

Ohio 44691, USA; mwilson@wooster.edu

Alatoform edgewise recliner bivalves of large size include mid Permian alatoconchids (ambonychioids) and late Triassic wallowaconchids (megalodontoids), but this life habit also occurs in early Mesozoic bivalves of moderate size: the early Jurassic Opisoma (astartids) and Anisian (early Middle Triassic) 'Myalina' ramanensis Brotzen, 1956 (myalinids). Opisoma is the least specialized alatoform, while 'M.' ramanensis is a well developed alatoform edgewise recliner. It is the second Triassic development of this habit and is the second adaptation of myalinids to alatoform life habits: the first being mid Permian alatoconchids. This life habit was most successful among bivalves during the change to Mesozoic-Cenozoic biotas established after the end-Permian mass extinction. The alatoconchid and wallowaconchid radiations occurred during times of warm climates and reef development, but 'M.' ramanensis appears during a time of longterm climate change.

'M.' ramanensis is found within the Gevanim Formation in the Negev Desert, occuring in great numbers as monospecific assemblages within deposits of nearshore shallow marine environments. It grew to 15 cm length and developed wings with acute folding, in contrast to the parallel folding of wings in alatoconchids and wallowaconchids, but it has other features characteristic of the larger alatoforms. It secreted large amounts of secondary shell within beak areas and basal surfaces, but the postero-dorsal shell walls remained thin. Secondary carbonate secretion occurred to the extent that valves of old adults are sometimes fused together along the hingeline. 'M.' ramanensis evolved from Myalina with changes in direction of flattening and loss of duplivincular ligament condition. Although midway in time between the alatoconchids and

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wallowaconchids, it is unrelated to either of those groups. The similarity of general form among alatoform edgewide recliners - flattened basal surface, pointed beak and elevated crest in an anterodorsal position - and occurrences with great numbers of individuals in monospecific accummulations shows the value of this life habit in shallow mud-bottomed environments during the Permian and early Mesozoic. The short duration of these adaptive events suggests alatoform bivalves were limited by needs to maintain large populations in these environments and thus subject to availability of large amounts of food.

LATE TRIASSIC WALLOWACONCHID BIVALVES (MEGALODONTOIDS) OF THE UNITED ARAB EMIRATES: FUNCTIONAL WING DESIGN ON LARGE BIVALVES FOR

ALATOFORM EDGEWISE RECLINING LIFE HABIT

Yancey, T. and Woods, M.

(1*) Department of Geology & Geophysics, Texas A&M University, 3115 TAMU, College Station, Texas 77843-

3115, USA; tyancey@tamu.edu (2) British Geological Survey, Keyworth, Nottingham

NG12 5GG, England; maw@bgs.ac.uk

Huge aggregates of wallowaconchid bivalves occur in late Triassic (Norian) strata within the Hajar Range (Oman Mountains) of the United Arab Emirates on the Arabian Peninsula. Densely crowded monospecific assemblages occur at several levels within the Ghalilah Formation, extending hundreds of metres laterally within beds of shallow marine deposits. These peri-Gondwanan individuals are an undescribed genus of wallowaconchids, differing from the type genus in having a more flattened shell and lighter shell construction and possessing an angular ridge on the dorsal surface along the outer edge of the body chamber. Adult shells grew to 50 cm or larger, with a width nearly as great as length, but a height of no more than 10 cm and thin chambered wings of 0.5 cm total thickness. These wallowaconchids developed a chambered wing design that demonstrates the functional value of chambering within tightly folded wing structure. The wing fold has parallel limbs and extends for 15 to 20 cm beyond the body cavity, but valve wall thicknesses are only about 2 mm thick and total thickness averages 5 mm, for a width to thickness ratio ranging from 30:1 to 40:1 on adults. This thin wing is relatively light but potentially very weak without

chambering, thus adding chamber walls extending across the space between fold limbs creates a strong structure using a minimum of shell and reducing shell mass and weight, with the additional advantage for the animal of creating barriers to protect the main body mass from exposure if a wing is broken. The wings were used as snowshoes for maintaining position as an edgewise recliner on a mud substrate and the utility of the design allowed animals of even large size and relatively high body weight to live as snowshoe recliners on soft mud substrates. In contrast to the light weight construction of wings, the animal secreted much secondary carbonate on the body chamber of the shell to serve as a stabilizing mass to prevent displacement by strong bottom currents or wave activity.

INTER- AND INTRASPECIFIC GENETIC VARIABILITY IN THE VENERID BIVALVE,

MERETRIX SPP. IN THE WESTERN PACIFIC AND INDIAN OCEAN

Yashiki, A., Imai, H., and Yamaguchi, M.

University of the Ryukyus, Faculty of Science, Nishihara, Okinawa, Japan, 903-0213; (1*)

k058563@eve.u-ryukyu.ac.jp

The genus Meretrix is one of commercially important bivalves in Asia and East Africa. These clams are found on tidal flats and sandy beaches in the Indian Ocean, Southeast Asia, Chinese mainland, Korean Peninsula and Japanese coasts. In this genus, there are at least nine recognized species, i.e., M. meretrix, M. casta, M. lusoria, M. petechialis, M. ovum, M. planisulcata, M. lyrata, M. lamarcki and M. attenuata. Previous work on Meretrix has focused on shell morphology, that often showed marked intraspecific variability. For that reason, species identification has frequently been confused in picture books and scientific literature. This genus is also said to be one of the poorly studied groups in spite of its economical importance. In this study, allozyme and the RAPD-PCR analyses were conducted to find the extent of inter- and intraspecific genetic variability.

Allozyme analysis of a total of twelve populations in six species, M. lusoria (Japan, Korea, Taiwan), M. lamarckii (Japan), M. petechialis (China, Korea), M. lyrata (China), Meretrix sp.1 (Ryukyu Islands), Meretrix sp.2 (Thailand, Mozambique), were examined at thirteen loci. Meretrix sp.1 from Ryukyu Islands was genetically distant from all other species (Nei's genetic distance D=0.96), although it shows shell characters similar to M. lamarckii. Moreover, the genetic distance

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between the Taiwanese and Japanese populations of M. lusoria showed a high degree of genetic differentiation (D=0.386). In Taiwan, seedlings of M. lusoria had been introduced during the 1920's from Japan and China, and had established itself as a cultured stock in Taiwan. Our results suggest that the putative Taiwanese population might represent a different species from M. lusoria. The RAPD-PCR analysis of fourteen populations of eight species, with two species (M. meretrix and M. casta from India) in addition to six species used in allozyme analysis, was conducted. The RAPD data were nearly consistent with the results of allozyme analyses. Meretrix sp.1 also showed a high genetic differentiation from all other Meretrix species examined. These results suggest that reexamination of current methods in species identification for the genus Meretrix, that are based solely on shell morphology, is needed.

HABITAT SELECTION OF UNIO CRASSUS

Zajac, K. and Zajac, T.

Institute of Nature Conservation, Polish Academy of Science 31-120 Kraków, Mickiewicza 33, Poland

Although mussels are one of the main elements of biomass in lotic environments, little is known on their behaviour. Channel reformation and large-scale movements of substrata can cause substantial mortality in their populations. In such unpredictable environment behavioural adaptations should be expected, enabling easiest reaction to changes in river channel functioning. We studied behaviour of the endangered freshwater mussel Unio crassus occurring in a small river in the Carpathian foothills (southern Poland). Individuals were exposed to experimental changes in its locations. We distributed ca. 200 individuals in a regular network throughout the section of a natural river channel, observing subsequently their behaviour.

Mussels were able to change their location within the whole studied river channel. They could also ascend to higher areas on the steep bank. They were moving little in riffle areas of the river, whereas in pools they were moving to large distances. They were actively aggregating behind a large rocky boulder (riffle) or at steep clay bank (pool). These places reflect U. crassus occurrences in natural rivers. The mussels were not displaced passively by water flow, because many moved upstream; telemetry also confirms that they were not washed downstream. The role of active directed individual movements of U. crassus individuals is very important for microhabitat selection. Mussel movements are not only the result of experimental conditions.

Individuals that should have found their optimal places during the experiments in 2004, were found in different places in the autumn of 2005, with the mean distance from their previous locations being ca. 5m (maximum over 13m).

It is concluded that due to channel reformation, frequent in mountainous rivers, mussels live there in a metapopulations, where probability of shoal disappearing must be balanced by probability of colonisation of a new site. This has serious consequences for river conservation and management.

EVOLUTION OF ACTIVE HOST-ATTRACTION STRATEGIES IN THE

FRESHWATER MUSSEL TRIBE LAMPSILINI (BIVALVIA: UNIONIDAE)

Zanatta, D.T. and Murphy, R.

Royal Ontario Museum, Department of Natural History, 100 Queen¹s Park, Toronto, ON Canada, M5S 2C6;

dave.Zanatta@utoronto.ca

Most freshwater mussels (Bivalvia: Unionoida) require a host, usually a fish, to complete their life cycle. Unionidae often show adaptations that increase the chances of their glochidia larvae contacting a host. A wide diversity of host attraction strategies (lures) have been observed in the freshwater mussel tribe Lampsilini. These lures often mimic a host prey item. Lures can either be derived from the mantle (actively moved by the female mussel) or as packages of glochidia (non-mantle derived, but often tethered to the mussel - termed conglutinates). We investigated the evolutionary relationships of the freshwater mussel tribe Lampsilini including 49 of the approximately 100 extant species including 21 of the 24 recognized genera. Mitochondrial DNA sequence data (COI, 16S, and ND1) were used to create a molecular phylogeny for these species. Parsimony and Bayesian likelihood topologies revealed that the use of an active lure arose early in the evolution of the lampsiline mussels. The mantle flap lure appears to have been the first to evolve with other lure types being derived from this condition. Apparently, lures were lost independently in several clades. Hypotheses are discussed as to how some of these lure strategies may have evolved in response to host fish prey preferences

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THE UNUSUAL SYSTEM OF MITOCHONDRIAL INHERITANCE IN

BIVALVES

Zouros, E.

Department of Biology, University of Crete, Heraklion, Crete, Greece

The phenomenon of doubly uniparental inheritance of mtDNA (DUI) has been found so far in four families of bivalves: Mytilidae, Unionidae, Pectinidae and Donacidae. It consists in the presence of two distinct mitochondrial genomes, one transmitted by the eggs (F) and the other by the sperm (M). In Mytilus (to which the rest of this abstract will refer exclusively) the maternal genome dominates the eggs and the somatic tissues of both females and males, and the paternal dominates the male gonad. Pure sperm contains only the paternal genome. There is a strong mother-dependent sex ratio in Mytilus, with some females producing practically no sons and others producing more than 90% sons. In fertilized eggs of females of the first type sperm mitochondria disperse randomly among blastomeres following egg division, in eggs from females of the second type they cosegregate staying closer to the cleavage furrow of the blastomere destined to produce the primordial cells. This indicates that sperm mitochondria behaviour is under the control of egg factors coded by the mother's nuclear genes and suggests a way to understand the linkage between sex determination and presence/absence of paternal mtDNA. A major question is whether the mtDNA itself plays a role in DUI, and the focus for this has been the genome's control region (CR). Recently a third genome was discovered (genome C). Its CR contains multiple domains of the CR of the M genome imbedded within the CR of the F genome. The sequence of the rest of the C genome is of the F type. The presence of this genome explains the observations that led to the "masculinization" hypothesis, i.e. that occasionally an F genome may invade the paternal lineage. The C genome was discovered in several widely separated populations, which raises the possibility that there might have been only one event of masculinization in the M. edulis/M. galloprovincialis species pair. It was also found in both males and females. DUI is a peculiarity that addresses several important questions, such as why cytoplasmic genomes are uniparentally inherited, and remains one of the most promising avenues for their answer.

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AUTHORS INDEX

A Abdallah, H. 23 Aguilar, J. 14 Aguirre, J. 63 Alonso-Gavilán, G. 63 Altaba, C.R. 14, 15, 52 Amaro, R. 32 Amler, M.R.W. 64, 65 Antunes, C. 71, 72 Aranishi, F. 16, 59 Araujo, R. 16, 24, 53 Armenteros, I. 38 Arntz, W. 20, 43 Astorga, M. 50

B Balseiro, P. 19 Barry, P.J. 17 Bassols, E. 15 Bataller, J.V. 17 Beata, M. 62 Benkendorff, K. 37 Bermúdez-Rochas, D.D. 24 Bieler, R. 18, 44, 56 Bingle, M. 41 Bogan, A.E. 41 Borges, L.M. 19 Brophy, D. 26

C Cáceres-Martínez, J. 19, 75 Campbell, D.C. 19, 20 Campbell, M.R. 20 Campos, A.C.d.A. 36 Carstensen, D. 20 Carter, J.G. 20 Carretero, M.A. 15 Catalá Roca, C. 57 Checa, A.G. 21, 22, 29, 67 Chiki-Aouimeur, F. 23 Civis, J. 38, 63 Clasing, E. 57 Coghlan, B. 38 Cordero, D. 60, 67 Cragg, S. 19 Crowley, L. 23 Cunha, M.R. 35

D D´Agosta, F.C.P. 36 De Renzi, M. 24, 65 Delgado-Blas, V.H. 49 Delvene, G. 24 Devers, J.B. 35

Díaz-Díaz, O. 25, 49, 74 Diz, A. 25, 61 Doherty, S.D. 26 Domènech, R. 36 Dreyer, H. 45, 73 Dridi, S. 26, 27 Dunca, E. 27, 28 Dyal, P. 74

E Eaton, R. 19 Edelman-Furstenberg, Y. 28 El Cafsi, M. 26, 27 El Hedeny, M.M. 29 Elorza, J. 43, 51 Esponda Fernández, P.H. 40 Esteban-Delgado, F.J. 22, 29 Evseev, G.A. 30

F Fang, Z. 30 Fernández, C. 32 Fernández, E. 39 Fernández, M. 15 Fernández-Moreno, M. 31 Figueras, A. 19 Francisco-Candeira, M. 32 Freire, R. 71 Forés, M 15 Fürsich, F.T. 46

G Galimany, E. 33 García-Carrascosa, A.M. 34 García-March, J.R. 33, 34, 45 García-Ortega, A.M. 19, 75 Gaspar, M. 71 Gatenby, C.M. 35 Génio, L. 35 Ghilardi, R.P. 36 Gibert, J.M. 36 Giménez, J. 43 Giráldez, S. 15 Gisbert, E. 52 Giribet, G. 37 Glavinic, A. 37 Glover, E. 74 Gofas, S. 37, 66 Gómez-Alday, J. J. 51 González Delgado, J.A. 38, 63 González-Tizón, A. 31, 32 Gosling, E. 26, 38 Gosselin, M.J. 39 Grahame, J. 35

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Grall, J. 47 Guderley, H. 47 Gudimov, A.V. 39 Guerra Muñoz, R.L. 40 Guerrero Campo, J. 57 Guilhermino, L. 71, 72 Guiñez, R. 50 Guzman, N. 39

H Haggart, J.W. 55 Harnik, P.G. 40 Harper, E.M. 29 Hartman, J.H. 41 Harzhauser, M. 55 Haszprunar, G. 41 Hautmann, M. 42 Held, C. 20 Hernández, J. 17 Herrmann, M. 20, 43 Higuera-Ruiz, R. 43 Hinz-Schallreuter, I. 46 Hochleitner, R. 69

I Imai, H. 77

J Jiménez-Berrocoso, A. 51 Jutson, M. 33

K Kappner, I. 44, 56 Kersting, D.K. 33, 45 Kiel, S. 35 Knapp, M. 45, 73 Kolotukhina, N.K. 30 Koppka, J. 46 Kossak, U. 46 Kraffe, E. 47 Kreeger, D.A. 35

L La Perna, R. 48 Lado-Insua, T. 61 Laudien, J. 20, 43 Lazareth, C.E. 39 Leduff, M. 47 Lee, T. 48, 49 Leese, F. 20 Liñero-Arana, I. 49, 74 Little, C.T.S. 35 Llavona, A. 50, 61 López, G. 50, 51 López, M.A. 52

M Machado, D.M.d.C. 52 Machordom, A. 16, 53

Magan, I. 49 Malchus, N. 53, 54, 55 Mandiç, O. 55 Márquez-Aliaga, A. 34 Martínez-Lage, A. 31, 32 Marty, Y. 47 Matsukuma, A. 56 Maynou, F. 62 McCormack, G. 17 Méndez Felpeto, J. 31 Méndez, J. 71 Mikkelsen, P. 18 Mikkelsen, P.M. 56 Montserrat, S. 15 Morán, P. 70 Moreno, R. 25 Mörth, M. 27 Murphy, R. 78 Mutvei, H. 27

N Nagel, K.O. 53 Nakamura Antonacci, K. 57 Navarro, J.M. 57 Neves, R. 58 Nixon, G. 55 Norrgrann, O. 28

O Ó Foighil, D. 49 Okimoto, T. 16, 59 Oliver, G. 59 Ondina, P. 32 Orchard, M.J. 55 Ortlieb, L. 39 Outeiro, A. 32

P Pablo, M. 67 Pasantes, J.J. 70 Passamonti, M. 59 Pastorino, G. 70 Patterson, M.A. 35 Penchaszadeh, P.E. 43 Peña, J. 60, 66, 67 Pérez, M. 50, 61 Pipe, R.K. 33 Pons, J.M. 23, 60 Pradillo, A. 17 Presa, P. 25, 50, 61 Printrakoon, C. 61 Pufahl, P.K. 55

R Ramón, M. 33, 62 Rawlings, T.A. 56 Reis, J. 53, 62 Rico García, A. 38, 63

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Rodríguez-Navarro, A.B. 29 Rogalla, N.S. 64, 65 Romdhane, M.S. 26, 27 Ros, S. 24, 65 Rosell, C. 15 Rovault, T. 52 Rouse, G. 37 Rozbaczylo, N. 25 Rueda, J.L. 66 Rufino, M. 71

S Saavedra, C. 60, 66, 67 Salas, C. 22, 37, 66, 67 San Miguel, E. 32 Sánchez, T.M. 68 Sanchis-Solsona, M. Á. 34 Sartori, A.F. 68 Scali, V. 59 Schiel, S. 20 Schneider, S. 69 Schniebs, K. 64 Schöne, R.B. 28 Semenikhina, O.Y. 30 Seoane, A. 61 Sha, J. 69 Signorelli, J.H. 70 Silva Hurtado, N. 70 Simpson, C. 40 Skelton, P.W. 71 Söderberg, H. 28 Sousa, R. 71, 72 Stanton, S.A. 72 Steiner, G. 45, 73

T Tavares, S.A.S. 36 Taylor, J. 74 Tëmkin, I. 61, 74 Templado, J. 45 Toledo, C. 16, 53 Toro, J. 50 Tozer, E.T. 55

U Urra, J. 66 Urrutia, G.X. 57

V Vanegas-Espinosa, V. 74 Varela, M. 32 Vásquez-Yeomans, R. 19, 75 Vicens, E. 23, 60

W Wahl, M. 46 Whitehouse, M. 27 Williams, S. 74

Wilson, M. 76 Winfield, I. 27 Wlodarska, M. 76 Woods, M. 77

Y Yamaguchi, M. 77 Yancey, T. 76, 77 Yashiki, A. 77

Z Zajac, K. 78 Zajac, T. 78 Zanatta, D.T. 78 Zapater Galve, M. 57 Zouros, E. 79