ACRITARCH NEWSLETTER N° 20DECEMBER 2004

Editors: Marco Vecoli (Villeneuve d’Ascq) and Reed Wicander (Mount Pleasant)

COMMISSIONE INTERNATIONALE DE MICROFLORE DU PALEOZOIQUEINTERNATIONAL COMMISSION ON PALAEOZOIC MICROFLORA

website: http://www.shef.ac.uk/~cidmdp/

Subcommission Acritarchs and Related Forms

ISSN 0258-543X

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CONTENTS

The Secretary’s column p. 3

The Chairman’s column p. 4

Memorial – Helen N. Tappan Loeblich p. 6

Memorial – Gusti Burmann p. 8

2nd phytoPal meeting p. 9

Abstracts of the 2nd phytoPal meeting p. 10

Acritarch classification working group report p. 17

News from acritarch workers p. 21

Acritarch publications, update p. 29

Acritarch publications, 2003 p. 31

Abstracts of conference presentations p. 33

Thesis abstract (Ludovic Stricanne) p. 35

Thesis abstract (Marco Quintavalle) p. 36

On the cover: two Veryhachium specimens linked together (photo by Paul Strother)

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THE SECRETARY’S COLUMN

Dear friends,

I would like to thank all those who have contributed to this Newsletter; fourteenacritarch workers from 8 different countries (and 5 continents) sent in theirreports. Compared to last year, however, I note a decrease in the contributionsfrom the east-European countries, which is a bit disappointing, also if one takesinto account the tradition for palynological studies of eastern european countries.The European Commission’s 6th Framework Programme for Research andTechnological Development (FP6) offers a lot of different possibilities of fundingfor collaborative research between European laboratories, and collaboration withthe “new” European state members is particularly encouraged. We shouldexplore this kind of possibilities. The web site of the 6th Framework Programmeis: http://www.cordis.lu/fp6/fp6_glance.htm and it is certainly worth to have a lookat what kind of possibilities are offered.

We open our newsletter with the sad news of the passing away of two importantpersonalities in palynological research: Helen Tappan and Gusti Burmann. We allknow the importance of their work for our research, and the memorials at p. 5 and7 rightly honour their work and their memory.

The abstracts presented at the second PhytoPal workshop held in the campus ofthe Universitty of Lille late in 2004 are reproduced.This newsletter contains also an interesting contribution on the progress of thework of the acritarch classification working group; the proposed subdivisions maybe a good starting point towards a “more natural” and, perhaps a moreuniversally accepted classification.

Two PhD thesis dealing with Lower Palaeozoic acritarchs were discussed thisyear, and their abstracts are reported.

Hoping to continue to receive your contributions, I wish you a happy andsuccessful 2005 (and happy reading of this newsletter…).

Marco Vecoli

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THE CHAIRMAN’S COLUMN

Dear members of the Acritarch Subcommission:

As I had hoped, the acritarch community had a strong showing at the XIInternational Palynological Congress last July in Granada, Spain. In the threeCIMP symposia (Precambrian Palynology, Lower Palaeozoic Palynology, UpperPalaeozoic Palynology), more than 25 acritarch papers were presented, as wellas several other papers in the Dinoflagellate Cysts and Dinoflagellate BiologySessions. This bodes well for a continued active and vigorous research programfor the future. I enjoyed all of the talks in the various sessions I attended and wasgreatly impressed at the diversity of research topics, as well as the quality of thepresentations. It was great seeing colleagues I hadn’t seen in several years, butit was also most encouraging to meet many of the younger acritarch researchers.They are the future of our discipline and their talks were some of the best at theconference.

I mentioned in my last column that the first meeting of phytoPal took place onDecember 11 and 12, 2003 at the University of Leicester. For those of you notyet familiar with this project, it is a three-year project funded by a LeverhulmeTrust Research Interchange grant awarded to Dr. Dick Aldridge (University ofLeicester), and whose objectives are to forge links between scientists interestedin Paleozoic palynology, particularly as it relates to the interplay betweenphytoplankton (principally acritarchs and prasinophyte phycomata) and climateduring the Paleozoic. PhytoPal was thus chosen as the ‘umbrella’ name forthose interested in the grant’s objectives.

At the initial management meeting last year, it was agreed that a phytoPaldatabase would be built, from which a Sepkoski-type Paleozoicmicrophytoplankton curve could constructed. Since that meeting, the phytoPalwebpage is up and running and can be accessed at:http://www.le.ac.uk/geology/glm2/phytopal.html.Here you will find information about the project as well as being able to downloadthe phytoPal Reference Database, which currently is 97 pages long and containsmost published acritarch references. The taxonomic database is still a work inprogress, but that will also soon be available. Dr. Gary Mullins is overseeing bothdatabases. If you are interested in this project, please visit the phytoPalwebpage.

The second phytoPal meeting and workshop took place in Lille, France onDecember 15, 16, 2004 with 13 talks scheduled to be presented. I was not ableto attend that meeting, so I can’t report on it. The last phytoPal meeting will beheld in conjunction with the American Association of Stratigraphic PalynologistsAnnual Meeting in St. Louis, Missouri, September 18-22, 2005. I hope many ofyou will be able to attend this meeting as we will be having a symposium in whichthe results of this three-year project will be presented.

I should also mention another project in which acritarch workers are activelyinvolved. IGCP project no. 503 “Ordovician Palaeogeography andPalaeoclimate” had its first meeting in Erlangen, Germany, September 1-3, 2004.The scientific goals of the project include understanding Early Palaeozoic

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biodiversity trends, Early Palaeozoic palaeogeographical reconstructions, EarlyPalaeozoic climate and climate modeling, palaeo-biogeographical scenarios fordifferent Early Palaeozoic fossil groups, and Early Palaeozoic palaeoecology, toname a few. The first session included a variety of talks on the topics justmentioned, including several acritarch presentations. This is another opportunityfor acritarch workers to be involved in interdisciplinary projects and for acritarchresearch to have a presence in different scientific fields. Check out the websitefor this project at http://www.pal.uni-erlangen.de/IGCP503/.

Lastly, I hope everyone responded to our Secretary’s call to let us know whatyou are doing. The Newsletter is one of the best ways to stay current on whatcolleagues are doing. Please send news items, address changes, and letters toour Secretary, Marco Vecoli for inclusion in the next Newsletter.

My best wishes for the New Year and I hope to see many of you at the AASPmeeting in St.Louis, Missouri in September, 2005.

Reed Wicander

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MEMORIAL

HELEN N. TAPPAN LOEBLICH (1917 – 2004)

With the passing of Helen Tappan Loeblich onAugust 18, 2004, the paleontologic communitymourns the loss of one its major figures andinternational leaders. Helen Tappan was bornon October 12, 1917 in Norman, Oklahomaand earned her B.S. degree (Phi Beta Kappa)in 1937 and M.S. degree in 1939 at theUniversity of Oklahoma. It was during this timethat she met Al Loeblich, Jr., whom shemarried on June 18, 1939 and began a life-long scientific collaboration that resulted inmajor advancements in micropaleontology andpalynology. She earned her Ph.D. in Geologyin 1942 at the University of Chicago with athesis on Texas and Oklahoma mid-Cretaceous foraminifera.

When Al received orders to report for militaryduty in 1942, Helen assumed all of Al'steaching duties at Tulane University andbecame the first woman faculty member ofTulane's College of Arts and Sciences (1942-1943). Following the end of World War II,Helen resumed her earlier work with the UnitedStates Geological Survey (USGS) when thefamily moved to Washington DC where Albecame Curator of Invertebrate Paleontologyand Paleobotany at the United States NationalMuseum.The Smithsonian Institution sent Al to Europeduring 1953-1954 to study the foraminiferal

collections in Europe's major museums and tocollect foraminiferal samples as backgroundmaterial for Helen and Al's work on theTreatise on Invertebrate Paleontology volumeon foraminifera. Helen obtained aGuggenheium Fellowship and together withtheir four children and Al's mother, spent ayear traveling throughout Europe. Theycollected more than two tons of rock samplesand Helen illustrated with a camera lucida allthe type specimens they studied at themuseums they visited.Following a two year stint (1954-1956) duringwhich Helen was an Honorary ResearchAssociate of the Smithsonian Institution, theLoeblich-Tappan family moved to California in1957 where Al headed a micropaleontologicalprogram at Chevron Oil Field ResearchCompany, and Helen worked part-time for theUSGS. In 1958, she began teaching at UCLA,and became a full-time faculty member in1966, full Professor in 1968, and ViceChairman of Geology from 1973-1975.During her tenure at UCLA, Helen advised,mentored, and inspired numerous students ingeology, paleontology, micropaleontology, andpalynology, including the author of thismemorial. Her breadth and knowledge in thefields of micropaleontology and palynology islegendary and she was an inspiration toeveryone with whom she came in contact,especially her graduate students. Helen wasmore than generous with her time and energy,serving on many editorial and society boards,and various university and professionalcommittees. She received numerous justlydeserved awards, including the 1982 Womanof Science Award from the UCLA MedicalCenter Auxiliary, the Paleontological SocietyMedal in 1983, and the Raymond C. MooreMedal for “Excellence in Paleontology” in 1984,to name just a few.Helen will undoubtedly be best rememberedfor her many seminal contributions to the fieldof paleontology as well as her prodigiousscientific output, both as sole author and incollaboration with Al. Between 1937 and 1994,

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either as sole or joint authors, they published272 scientific papers or books. Some ofHelen's more noteworthy papers include their1957 paper “Correlation of the Gulf andAtlantic Coastal Plain Paleocene and lowerEocene formations by means of planktonicForaminifera,” which won Best Paper Award inthe Journal of Paleontology; the 1964 two-volume Treatise on Invertebrate Paleontology,Part C. Protista 2. Sarcodina, chiefly‘Thecamoebians’ and Foraminiferida (alandmark publication); and their magnum opustwo-volume book, Foraminfiera Genera andTheir Classification (1987), which received the1988 Award of the Association of AmericanPublishers for the best Professional andScholarly book in the field of Geography andEarth Science. Helen's book The Paleobiologyof Plant Protists (1980) was voted the bookpublisher’s best non-fiction book for that yearand is still a valuable reference for anyoneworking in the field of plant protists.In the discipline of palynology, Helen and Alalso made major contributions and advancedthe science tremendously, setting a highstandard for others to follow. During the late1960s, Helen and Al commenced theirresearch on acritarchs, describing in greatdetail and beautifully illustrating numerousOrdovician, Silurian, and Devonian taxa,mainly from North America, and always fromwell-documented and stratigraphicallycontrolled sections. Some of their betterknown and important acritarch papers include"Morphology, ultrastructure and distribution ofPaleozoic Acritarchs" (Journal of Paleontology,1969); "Acritarch excystment and surfaceultrastructure with descriptions of someOrdovician taxa" (Revista Española deMicropaleontologia, 1969); "Surface sculptureof the wall in Lower Paleozoic acritarchs(Micropaleontology, 1972); and "Some Middleand Late Ordovician microphytoplankton fromcentral North America" (Journal ofPaleontology, 1978), as well as numerouspapers describing new genera and species.Helen's wide range of interests in geology,paleontology, and evolution led her to tackleglobal issues concerning the interrelationshipbetween the evolution of the marinemicrophytoplankton community and theevolution and extinction of marine andterrestrial plant and animal groups, as well as

how this affected atmospheric changesthrough time. Her seminal paper "Primaryproduction, isotopes, extinctions and thea tmosphere" in Pa laeogeography ,Paleoclimatology, Palaeoecology (1968) firstdealt with this issue, and subsequent papersthrough the 1980s refined and modified heroriginal hypothesis.Helen led by example. She demandedexcellence from herself and those with whomshe collaborated. If you were lucky enough tohave Helen as your advisor or a referee forone of your papers, you could be certain that ifthere was any weak logic or the data didn't fityour conclusions, she would find it. Becauseshe was a superb writer herself, her editorialcomments and corrections always made for abetter paper or thesis. And like the UnitedStates Army's slogan of "be all that you canbe," she instilled that sense of striving forexcellence in all of her studentsIn spite of the numerous honors, scientificaccomplishments, and international reputation,Helen was very humble and kind to everyone.She was quiet, soft-spoken, and verypersonable as well as being extremelygenerous with her time and expertise. Helenand Al had one of the most extensive reprintcollections in micropaleontology andpalynology, and it was always open to studentsand visiting researchers. I think I speak for allof Helen's students when I say that over theyears, we realize how lucky we were to havehad Helen as our advisor, both professionallyand personally.Helen had a lifelong commitment to education,and to commemorate that passion for learning,her daughter, Elizabeth Loeblich (whom kindlyprovided me with various facts andremembrances about Helen), has establisheda scholarship and research fund in Helen andAl’s name. Tax-deductible contributions maybe sent to:

Alfred R. Loeblich, Jr. & Helen N. Tappan LoeblichScholarship & Research FundCushman Foundation, MRC-121 Department ofPaleobiologyNational Museum of Natural HistoryWashington, DC 20500-0121

Reed Wicander

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OBITUARYGUSTI BURMANN (1938 – 2004)

Gusti Burmann passed away after a short, butsevere illness on the 28. of February 2004.Born in Berlin as Augusta Burmann in 1938,she started to study Geology/Palaeontology in1956 at the Humboldt-University at Berlin. In1959 she received a stipend for studies at theUniversity of Leningrad (Soviet Union). Thereshe did her advanced studies with B. W.Timofejew who got her interested inProterozoic and Palaeozoic biostratigraphy.For her Diploma-Thesis she worked on theacritarchs of Thuringia.From 1963 on G. Burmann worked at theZentrales Geologisches Institut (ZGI) at Berlin,the main geological survey of the EasternGerman Republic (DDR), and published duringthis time period 18 papers on organicmicrofossils, including acritarchs, pollen andspores and chitinozoans from metamorphicrocks. In 1977, after political and personal

problems, she left this institution and workedfor many years outside of her field in variouspositions as librarian and applied geologist.After the reunification of Germany G. Burmannused a second chance to do scientific researchin her specialty. From 1993 on, supported bythe German funding agengy (DFG), she wasable to work on microfossils in deformed rocks.Since the beginning of the 1990s G. Burmannwas one of the most active members of theGerman Subcommission „Proterozoic-Silur“, agroup of scientists in germany who wereconcerned with the Stratigraphy of thePrecambrian and Early Palaeozoic. All theseactivities resulted in more than 15 well writtenand widely accepted papers.Gusti Burmann was a friendly and cheerfulcolleague, who participated vividly with herBerlin wittiness in gatherings and discussions.We miss her.

Barbara MohrMuseum f. Naturkunde

Invalidenstrasse 4310115 Berlin, Germany

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THE SECOND PHYTOPAL MEETING AND WORKSHOP;

UNIVERSITE LILLE 1,VILLENEUVE D’ASCQ, 15 DECEMBER 2004

Delegates (from left to right). Marco Vecoli, Dick Aldridge, Ken Dorning, Emmanuelle Javaux, ThomasServais, Cristiana Ribecai, Stewart Molyneux, Malgorzata Moczydlowska-Vidal, Paul Strother, ElenaRaevskaya, Gary Mullins.

The second Phytopal Meeting was hosted bythe “Laboratoire de Paléontologie etPaléogéographie du Paléozoïque”, in thecampus of the University of Lille 1, Villeneuved’Ascq, northern France. As it can be seen bythe abstracts of the talks presented, the focuswas on different aspects of acritarch research:biostratigraphy, morphological analysis,b i o d i v e r s i t y , p a l a e o e c o l o g y , a n dpalaeobiology. We can say that an effort iscurrently being done by acritarch workers, toput their palynological studies in a broaderperspective, that is to understand therelationships of oceanic microphytoplanktonwith global changes affecting the biosphereand the geosphere in the Palaeozoic. The (in acertain sense) more “classical” accuratetaxonomical studies of particular groups(“plexa”) is still important, and contributes toincrease our knowledge of this fascinatingphytoplanktonic fossil group.

I should like to remember here that a “Phytopalforum” exists: an e-mail based message boardto use for duscussion among workers on anyacritarch-related topic. Anyone interested inPalaeozoic palynology can join this virtualforum by sending an email with the simplecommand line “subscribe to phytopal Yourname” to listserver@le.ac.uk, remembering toleave the subject line blank. For furtherinformation you can send a message to GaryMullins: glm2@leicester.ac.uk

The database (still under construction) can beaccessed online:

Mullins, G.L., Aldridge, R.J. and Dorning,K.J. 09/09/2004.The phytoPal reference database, 97pp.http://www.le.ac.uk/geology/glm2/phytopal/reference_database.pdf

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ABSTRACTS OF TALKS AND POSTERS PRESENTED AT THE SECOND PHYTOPAL WORKSHOP

Late Cambrian Lusatia dendroideaBurmann, 1970: taxonomy, biostratigraphyand paleobiogeography.

Roberto Albani1, Gabriella Bagnoli1, ElenaRaevskaya2, 3 and Cristiana Ribecai1.

1. Dipartimento di Scienze della Terra, Universit_ di Pisa,via S. Maria, 53, I-56126 Pisa, Italy (ribecai@dst.unipi.it).2. UMR 8014 du CNR (Labortoire de Paléontologie etPaléogeographie du Paléozoïque), Université desSciences et Technologie de Lille, Villeneuve d’AscqCedeux, F-59655, France. 3. Institute of PrecambrianGeology and Geochronology, Russian Academy ofSciences, Makarova Emb., 2, 199034, St. Petersburg,Russia

During the Late Cambrian a high number ofnew forms at specific and generic levelsoccurred in acritarch communities. Relativelyquick changes in taxonomical content of theseassociations and their wide undifferentiatedgeographical distribution make acritarchs veryuseful for the Cambrian biostratigraphy.However, their systematics, based only onmorphological cri teria, often causestaxonomical confusions when a large variabilitywithin different morphotypes and clearintermediate forms are present. Therefore, adetailed revision of key acritarch taxa isseriously required.In the present work we focus our interest onspecies Lusatia dendroidea Burmann, 1970,which potential ly can be a goodbiostratigraphical marker possessing distinctiveeasily recognizable morphological features andranging within a short interval of the LateCambrian. The type material, from which thisspecies was originally described, came frommetamorphosed (and possibly reworked) rocksof Lausitz area of Germany. Being frequentlyfragmented both holotype and paratype wereonly illustrated in graphic drawings (Burmann,1970). The species exhibits a well-pronouncedbipolar asymmetrical morphology of triangularacritarch. However, because of intricateramifications of rather long processes,specimens are often not preserved completely.Central bodies with only basal parts ofprocesses more commonly occur in acritarchassemblages, that hampers their identification.

New material from Cantabrian Zone (Spain)and Severnaya Zemilya Archipelago (ArticRussia) provides abundant and exceptionallypreserved representatives of Lusatiadendro idea. Based on this material andreinvestigation of a coeval collection fromMoscow sineclise (Volkova, 1990) morphology,variability, and possible relationship withclosest morphological groups, stratigraphicaldistribution and palaeobiogeographicalallocation of this species have been studied indetails.

Talk

The Cambro-Ordovician acri tarchVulcanisphaera

Mathilde Blanchon, Elena Raevskaya, ThomasServais and Marco Vecoli

Laboratoire de Paléontologie et Paléogéographie duPaléozoïque (LP3), UMR 8014 du CNRS, Sciences de laTerre, SN5, USTL, F-59655 Villeneuve d’Ascq, France.

The acritarch genus Vulcanisphaera Deunff,1961, and its type species V. africana werefirst described from Cambro-Ordoviciansequences of the Algerian Sahara. A firstdetailed revision of the genus, with adescription of three new species of theTremadocian of Shropshire, England, wasprovided by Rasul (1976). Additional specieswere subsequently described from differentother areas, including Spain, France, Poland,and Canada.The revision of the literature shows that over30 species have been attributed to the genus.The revision of the data available in previouslypublished papers, together with thereinvestigation of large populations ofVulcanisphaera from the type-localities inAlgeria and England, allow a new classificationconcept and a revision of the biostratigraphyand of the palaeobiogeography of the genus.The revision indicates that Vulcanisphaerashows a large intraspecific variability. From the31 species described in literature, 11 can notbe maintained within the genus. Threemorphotypes can easily be distinguished and

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could be retained as species: Vulcanisphaeraafricana, V. capillata, and V. simplex. The 17remaining taxa previously described asspecies could be classified as infraspecifictaxa. At the generic level, Vulcanisphaera isclearly distinguished from other acritarchgenera, although some relations exist with thegenera Cristallinium Vanguestaine, 1978, andTimofeevia Vanguestaine, 1978.In terms of biostratigraphy, the speciesattributed to the genus Vu lcan isphaeradescribed from the Precambrian clearly do notbelong to the genus. The first Vulcanisphaeraspecies appear in the Middle Cambrian,indicating a First Appearance Datum (FAD) inthe Pardoxides paradoxissimus trilobiteBiozone in eastern Newfoundland. However,Vulcanisphaera is rare in the Middle Cambrian,and the genus only becomes very abundant inthe Upper Cambrian. It reaches its highestmorphological variability in the latest Cambrianand during the Tremadocian.Palaeogeographically, as most acritarchgenera of the Cambrian-Ordovician transition,the genus shows a cosmopolitan distribution,occurring from high latitudes in the southernhemisphere to lower, near-equatorial latitudesworldwide.

Talk

Palaeozoic phytoplankton abundance anddiversity: evidence from the acritarch andprasinophycean algal record

Ken J. Dorning

Pallab Research, 58 Robertson Road, Sheffield S6 5DX,England and Palynology Research, University ofSheffield, England

Examination of the absolute numbers ofpreserved organic-walled phytoplankton,expressed as numbers per gram in samples ofsedimentary rock, provides indications of pastoceanic and marine shelf productivity. Thisdata can be directly compared with the speciesdiversity values for each sampled horizon. Forsamples from eastern Avalonia, high absoluteabundance values are recorded in the latestCambrian and Tremadoc, together with part ofthe late Ludlow in the Silurian. Moderate tohigh species diversity is recorded through theCambrian, Ordovician and Devonian, while low

species diversity is present through most of theCarboniferous and early Permian.

Talk

Palaeozoic phytoplankton abundance anddiversity: palynomorph assemblagevariation within late Wenlock carbonateshelf environments of the Farley Member ofthe Coalbrookdale Formation and MuchWenlock Limestone Formation

Ken J. Dorning1 and Craig Harvey1,2

1. Pallab Research, 58 Robertson Road, Sheffield S65DX, England and Palynology Research, University ofSheffield, England. 2. Current address A/S Norske Shell,Postboks 40, N4098, Tananger, Norway.

In recent years there has been a significantincrease in the number of quantitativepalynological studies undertaken in thePalaeozoic based on the absolute numbers pergram of rock. The quantitative distribution ofacritarchs as well as chitinozoans and sporescan be used to determine palaeoenvironments,and identify changes in palynologicalassemblages related to phytoplanktonabundance and diversity. These changes inthe acritarch and chitinozoan assemblagesmay be related to nutrient supply, associatedwith alternating wetter and drier palaeoclimatesduring the Silurian, linked to the deep oceanwater forced global climate Primo andSecundo episodes and events.

Informal discussion

Palaeozoic phytoplankton abundance anddiversity: acritarchs, prasinophycean algaeand chitinozoans from the Devonian ofVenezuela

Craig Harvey1,2 and Ken J. Dorning1

1. A/S Norske Shell, Postboks 40, N4098, Tananger,Norway. 2. Ken J. Dorning, Pallab Research, 58Robertson Road, Sheffield S6 5DX, England andPalynology Research, University of Sheffield, England.

The absolute numbers of preserved organic-walled phytoplankton, including acritarchs andprasinophytes, together with chitinozoans andspores, provides evidence of marine andterrestrial palaeoproductivity. Samples from the

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Devonian Campo Chico Formation fromwestern Venezuela show very variableacritarch and prasinophyte absolute numbersand diversity values. The Caño del OesteFormation and Lower Member of the CampoChico Formation yielded abundances between50-360 acritarchs per gram. The UpperMember of the Campo Chico Formationexhibited abundances of 517 - 44,000acritarchs per gram, and between 1-128chitinozoans per gram. The variationsobserved can be attributed to changes inphytoplankton productivity and terrestrialsediment dilution.

Informal discussion

Improving our understanding of earlybiosphere evolution and diversification,using a combination of microscopy andmicrochemistry of single acritarchs

Emmanuelle J. Javaux1 and Craig P. Marshall2in collaboration with Andrew H. Knoll3, AlainLeHérissé4, Malcolm R. Walter2, and ShuhaiXiao5

1. Department of Astrophysics, Geophysics andOceanography, University of Liège, 17 Allée du 6 Août,B5c, Belgium. 2. Australian Centre for Astrobiology,Department of Earth and Planetary Sciences, MacquarieUniversity, Sydney, NSW 2109, Australia. 3. Departmentof Organismic and Evolutionary Biology, HarvardUniversity, Cambridge, MA, USA. 4. UMR Domainesocéaniques, University of Brest, France. 5. Virginia Tech,VI, USA.

Acritarchs are conventionally interpreted asalgal cysts but most probably include a largerrange of organisms such as prokaryotes,heterotroph protists or even parts ofmulticellular beings. Beside a few cases, thebiological affinities of Proterozoic andPaleozoic acritarchs remain largely unknown.However these fossils record crucial steps inthe early evolution and diversification of thebiosphere. Thus new approaches arenecessary to resolve the biological affinities ofearlier autotroph and heterotroph organisms,thereby improving our understanding ofmicrobial Proterozoic and Paleozoicpaleobiology and food webs.Comparative biology is useful when earlyorganisms display already characteristicmorphological attributes, but this rarely occurs

(for example early dinoflagellates might notshow tabulation). Study of wall ultrastructurecan differentiate between prokaryotic andeukaryotic acid-resistant microfossils, and, insome cases, even identify prasinophycean andchlorococcalean green algae. Combiningmicroscopy (light microscopy, SEM and TEM)with microchemical analyses of individualmicrofossils offers further insights into thepaleobiology and evolution of earlymicroorganisms. Micro-Fourier transforminfrared (FTIR) spectroscopy and laser micro-Raman spectroscopy are used to elucidate themacromolecular structure and biopolymercomposition of individual Neoproterozoic(Tanana Fm, Austral ia) and earlyMesoproterozoic (Roper Group, Australia andRuyang Group, China) acritarchs of lowthermal maturity. New microscopic study oflate Paleoproterozoic shales from China(Chuanlinggou Formation) and Australia(Mallapunyah Fm) permits to extendsignificantly the stratigraphic range of fossilevidence for early eukaryotes. Further work isongoing to characterize the morphology,ultrastructure and chemistry of Proterozoic andPaleozoic microfossils, as well as extantmicroorganisms with resistant cell walls.

Talk

The plexus of Cambrian genus Skiagia asinnovative morphology of cyst-builders

Malgorzata Moczydlowska-Vidal

Uppsala University, Department of Earth Sciences,Palaeobiology, Norbyvägen 22, SE-752 36 Uppsala,Sweden.

The early Cambrian radiation of phytoplanktonwas one of the most conspicuous biotic eventsin the period, resulting in the appearance oftens of new species with complex morphologyand multi-modal dimensions. This associationof microbiota lasted for ca. 15-20 million years(Myr), coinciding with the appearance ofseveral new clades of bilaterians, and becameextinct, except of a few species, before the endof Cambrian. A morphologically distinctive anddiverse plexus of the genus Skiagia Downie,1982 is characterized by the presence ofprocesses with innovative funnel-shaped tipsbut otherwise it shows a re-combination of

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other features such as various proportions ofprocess length and vesicle diameter, shape ofprocesses and their abundance. The genushigh disparity resulted in a number of speciesdescribed but it may reflect insteadinfraspecific variability, ecological adaptationand/or various stages in the development ofthis cyst-builder. The discovery of thespecimens with the internal body suggests thatthe Skiagia microorganism produced process-bearing cyst, the outer envelop surrounding thecyst or a vegetative cell occasionallypreserved, and a reproductive/dormant internalcell. There are probably three stages in the lifecycle of S k i a g i a although only theacanthomorphic cysts are common Cambrianmicrofossils. This first record of a cyst withfruiting cell is from South Australia, the ArrowieBasin, but the genus Skiagia is worldwidedistributed in the Lower and Middle Cambrianstrata of Baltica, Avalonia, Armorica,Greenland, China and Australia. The genusSkiagia and its species are taxonomicallyrevised, based on observations of new materialand re-examination of the type collections. There-evaluation follows the taxonomic conceptsproposed recently to accommodate themorphologic variety of acritarchs from Chinaand Australia. The synonymy established hereand the recognition of certain morphologic taxais intended to simplify the identification and toeliminate some superfluous taxa.

Talk

A review of Lower Cambrian palynology inthe NW Highlands, Scotland:biostratigraphical, biogeographical andenvironmental considerations

Stewart Molyneux

British Geological Survey, Keyworth, Nottingham NG125GG, UK.

Palynological investigations of the Cambro-Ordovician succession of NW Scotland havefocussed on the Lower Cambrian Eriboll andAn t-Sròn formations. Downie (1982)investigated samples mainly from the FucoidMember (An t-Sròn Formation) with additionalsamples from the Pipe Rock Member (EribollFormation) and Grudaidh Formation (DurnessGroup). Samples came from Eriboll in the

north, Skiag Bridge, Knockan Cliff, and Ord onSkye. Downie’s original samples have beensupplemented for this study by samples fromthe Basal Quartzite Member (EribollFormation), Pipe Rock Member, FucoidMember and Grudaidh Formation from SkiagBridge, Knockan and Ullapool.A consistent pattern of acritarch distributions inthe Cambro-Ordovician succession of NWScotland has emerged from both studies. Themost diverse assemblages have been obtainedfrom the Fucoid Member. In contrast, samplesfrom other parts of the succession were eitherbarren or yielded low diversity assemblages,often comprising only sphaeromorphacritarchs. On this basis, assemblages fromthe Basal Quartzite Member and Pipe RockMember are consistent with nearshoreenvironments, whereas the increase indiversity in the Fucoid Member suggests amarine flooding event that brought deeperwater marine facies onto the Laurentianmargin. The palynological data from the Eribolland An t-Sròn formations can be interpreted asthe product of a single transgressive event. Inaddition, trends within the Fucoid Member canbe interpreted as indicating more than onetransgressive phase separated by shallowingevents. Downie (1982) suggested twotransgressive events in the succession atSkiag Bridge, but there are possibly three,depending on whether samples in the upperpart of the succession are interpreted as beingbarren due to environmental or post-depositional effects.The microflora from the Fucoid Membercompares most closely with those from theupper part of the EEP succession, and mainlywith that from the Vergale ‘horizon’. This alsosuggests correlation with the ‘Holmia series’ ofNorway. Comparison with Laurentiansuccessions is more limited, mainly because ofless data, but assemblages comparable withthat from the Fucoid Member have beendescribed the Buen Formation of northGreenland (Vidal & Peel 1993) and the BastionFormation of east Greenland (Downie 1982).

Downie, C. 1982. Lower Cambrian acritarchs fromScotland, Norway, Greenland and Canada. Transactionsof the Royal Society of Edinburgh: Earth Sciences, 72,257-285.

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Vidal, G & Peel, J. S. 1993. Acritarchs from the LowerCambrian Buen Formation in North Greenland.Grønlands Geologiske Undersøgelse, Bulletin 164, 35 pp.

Talk

The phytoPal database and the diversity ofthe Palaeozoic microphytoplankton

Gary L. Mullins

Department of Geology, University of Leicester,University Road, Leicester LE1 7RH, United Kingdom.

A database of taxonomic and stratigraphicalinformation for all of the described Palaeozoicmicrophytoplankton is being constructed. ThephytoPal database currently contains therecords of 899 genera and 5301 species and‘subspecies’. Stratigraphical information, in theform of metadata, is known for all except 535taxa. Analysis of this metadata has beenundertaken to identify the major trends in thediversity of the Palaeozoic microphytoplanktonand to recognize areas where more research isneeded.The diversity of the microphytoplankton,represented by a count of the number of taxa,is illustrated for each of the standard stages ofthe ICS/IUGS International StratigraphicalChart. The diversity curve obtained from thephytoPal database is more complex than thatof Tappan and Loeblich 1973, but has somesimilarities with the species diversity curve ofStrother 1996, text-fig. 9.The phytoPal diversity curve shows severalpeaks in the number of acritarch species.These peaks occurred in the Ediacaran-LowerCambrian, Tremadocian-Darriwilian, Telychian-Ludfordian and Frasnian-Famennian. Loweracritarch diversity occurred in the Middle-Upper Cambrian, Ordovician Stage 6-Aeronianand P_ídolí-Givetian. A major decline inacritarch diversity occurred in the Tournasian(Lower Carboniferous). The diversity ofprasinophyte algal species increased steadilythrough the Ordovician and Silurian andreached a peak in the Frasnian andFamennian, before declining rapidly in theTournasian. To assess the validity of thesediversity fluctuations key datasets need to beidentified that accurately record the distributionof microphytoplankton through periods ofapparent diversity change.

Tappan, H. and Loeblich, A. 1973. Evolution of oceanicplankton. Earth Science Reviews, v. 9, 207-240.

Strother, P. K. Chapter 5. Acritarchs, p. 81-106. In.Jansonius, J. and McGregor, D. C. (eds). Palynology:priciples and applications. American Association ofStratigraphic Palynologists Foundation, volume 1.

Talk

Middle-Late Ordovician phytoplanktoncommunity (acritarchs and Chitinozoa)from the inner Siberian basin

Elena Raevskaya1, T. Tolmacheva2, RobertoAlbani3

1. Institute of Precambrian Geology and GeochronologyRAS, Makarova emb., 2, 199034 St. Petersburg, Russia.2. All Russian Research Geological Institute (VSEGEI),Sredniy pr., 74, 199106 St. Petersburg, Russia. 3.Dipartimento di Scienze della Terra, Università di Pisa,Via S. Maria, 53, I-56126 Pisa, Italy.

Being one of the most complete Ordoviciansuccessions in Siberia the Kulumber Riversection (N 68.0º, E 88.8º) is considered as amain polygon for the regional stratigraphysince early 50th. Abundant macrofossils( t r i lobi tes, brachiopods, ostracodes,monoplacophorans etc.) provide data for high-resolution biostratigraphy. However regionalsubdivisions are not easy to correlate withBritish standard because of endemic benthicfossils.Middle-Late Ordovician interval represented byIl’tykskaya, Angirskaya, Amarkanskaya andZagorninskaya Formations was sampled forpalynological study. Graptolite findings in thelower part of the last formation providecorrelation with N. gracilis graptolite Zone ofthe base of the Upper Ordovician. OnlyAngirskaya and Zagorninskaya Formationscomposed of dolomites, clayey limestones,bioclastic l imestones, si l tstones andmudstones of relatively deeper depositionsyielded diverse microphytofossils of moderatestate of preservation. Among them acritarchs(Baltisphaeridium, Dasidorus, Liliosphaeridium,Lophosphae r i d i um , M i c rhys t r i d i um ,Rhopa l iophora , Pete inosphaer id ium,Sacculidium, Solisphaeridium and others),prasinophytes (Leiosphaeridium, Tasmanites),scolecodonts and Chitinozoa (Conochitina,Cyathochitina, Desmochitina, Eisenackitina,

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Lagenochitina, Rhabdochitina) have beenidentified.Investigated phytoplankton associations fromnorthern Siberia are taxonomically similar tothe well known Baltic assemblages, butcharacterized by comparatively poor speciescomposition. This feature, however, may be aresult of less favourable sedimentologicalconditions in the studied succession.

Talk

Which physiochemical factors controlphytoplankton diversity?

Paul K. Strother

Palaeobotany Laboratory, Department of Geology andGeophysics, Weston Observatory of Boston College,Weston, Massachusetts USA

The distribution of organic-wall phytoplankton(OWP) over Phanerozoic time as recorded instanding taxon diversity curves of acritarchsplus prasinophyte and dinoflagellate cysts,shows long-term trends that are disjunct fromthe classic trends of benthic invertebrates.Most researchers who have discussed thesetrends have attributed this distribution to aprogressive increase in nutrient availabilityover time, but, in my view, there is a goodmatch between OWP distribution with changingseawater chemistry as promoted by LawrenceHardie and others over the past 20 years.Nutrient availability scenarios use the classicRedfield ratio as an explanation for N+Pcontrol of phytoplankton diversity. Although in“ecological” time N+P availability can controlphytoplankton distribution, there is no evidencethat N+P availability has been the mainselective force in creating species diversity inthe phytoplankton. Changing seawatercomposition, as controlled by refluxing rates atmid-ocean spreading centers, affects Ca+2,Mg+2, K+, and HCO3

- concentrations. Inaddition, changes in atmospheric CO2composition over time can affect CO2availability in ocean surface waters, becauseatmospheric CO2 is in equilibrium with oceansurface water. Given the diversification of OWPduring high levels of CO2 availability, thedecline in atmospheric CO2 at the Devonian -Carboniferous boundary could have been afactor in their demise. Any evaluation of OWP

diversity trends should take into account thepossibility that carbon assimilation and ionchannel chemistry could have played a role inphytoplankton speciation to get beyond simpleN+P limiting nutrient models.

Talk

Middle and Late Cambrian acritarchs fromthe Inner Clastic Belt of Laurentia

Paul K. Strother

Palaeobotany Laboratory, Department of Geology andGeophysics, Weston Observatory of Boston College,Weston, Massachusetts USA.

Middle to Late Cambrian rocks depositedaround the cratonic margin of Laurentia in theUnited States preserve a record of non-marineand perhaps shallow marine palynomorphs.Palynomorphs are found in both outcrop and incores. These include cryptospores,problematic microfossils, “leiospheres” andacritarchs. Although cryptospores and similarproblemat ic forms dominate mostassemblages, acritarchs from cores from theConasauga Group in Oak Ridge Tennesseecan comprise 1 % of total palynomorph count.These Middle Cambrian assemblages aretypified by small (8 to 20 µm) acanthomorphicforms including Aster idium tornatum,Celt iberium cf. C . sp. B (Downie 1982),Cymatiosphaera luminosa, Lophosphaeridiumsp., several probable species of Skiagia, and apossible new acritarch genus with a partiallydeveloped reticulum and distinctive processes.Samples of later Cambrian age from thewestern US conta in monospeci f icassemblages of Polygonium.

Acritarchs from the Middle CambrianConasauga Group are a close match to abasinal assemblage from the Burgess Shalethat is being studied by Kevin Gostlin at theUniversity of Toronto. In the US, they are foundin near-shore and shallow marine carbonatesettings. Given that these tiny spiny acritarchsare distributed over such a wide range ofdepositional settings, perhaps they represent ageneral trend for the Middle Cambrian withinLaurentia, rather than simply marking variationbetween depositional settings. It would be

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interesting to see if such a trend is global innature.

Talk

Did microplankton “explosions” trigger theOrdovician Biodiversi-fication Event?

Marco Vecoli and Oliver Lehnert

Laboratoire de Paléontologie et Paléogé-ographie duPaléozoïque (LP3), USTL - UMR 8014 du C.N.R.S. - CitéScientifique, F-59655 Villeneuve d'Ascq, France .

The Ordovician was a time of continuingcontinental break-up and dispersal, extensivevolcanic activity, and major radiations amongalmost all fossil groups. Different authorsalready suggested a direct correlation betweenthe tectonic evolution, volcanism and theOrdovician radiation events. However, asSepkoski and Sheehan already pointed out in1983, “there was no immediately obviousphysical trigger for such a great burst ofevolutionary activity“ that could have causedthe Ordovician biodiver-sification.We analyze the relationships betweenbiodiversif ication patterns in marineinvertebrates and oceanic microphytoplanktonduring Ordovician times, for understanding theevolution of primary producers and its role inthe so-ca l led “Grea t Ordov ic ianBiodiversification Event“.Diversity and/or density records ofmicrophytoplankton cysts (acritarchs) in thesediments cannot be taken directly as ameasure of oceanic productivity (a mistake thathas been done in previous studies), butevidence from the fossil record of consumersseems to indicate that primary productionincreased strikingly during the Ordovician.Increasing complexity in food webs duringOrdovician times is suggested by the followingfacts: 1) the “Ordovician explosion“ in marinemacroinvertebrate diversity; 2) innovation ofplanktotrophy in molluscs larvae; 3) the firstappearance and radiation of graptolites,phyllocarids, several groups of echinoderms,and chitinozoans, as well as the diversificationof radiolarians.The observation of major diversification eventsin all fossil groups implies drastic changes inthe basal food chain and a tremendousincrease in primary production (“plankton

explosions“). This major change waspresumably the main trigger for the “GreatOrdovician Biodiversification Event“.

Talk

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ACRITARCH CLASSIFICATION WORKING GROUP REPORT FOR 2004

Ken J. Dorning,k.j.dorning@sheffield.ac.uk

At this time, it seems appropriate to summarisesome of the current thinking on acritarchclassification. Over the past few years therehas been greater emphasis in groupingtogether forms with similar characteristics,rather than attempting to subdivide all thedescribed acritarch genera into totally artificialgroupings. Some of these groupings havebeen noted in previous reports of the AcritarchClassification Working Group of the CIMPAcritarch Subcommission, reported in previousissues of the Acritarch Newsletter. Thefollowing groupings have been published aspart of the acritarch chapter within themicrofossils section of volume 3 of theEncyclopedia of Geology. In a few cases,additional genera have been included in thislisting. Suggestions for additional groupingsand suggestions for additional genera to beincluded in current groupings will be mostwelcome. Please send these to the workinggroup coordinator, Ken J. Dorning by email atk.j.dorning@sheffield.ac.uk.

In general, the acritarchs and prasinophyceanalgae are considered as form genera, and assuch, it is seem as inappropriate to use aformal classification system. For this reason,the acritarchs are generally treated as incertaesedis microfossils, organic-walled microphyto-plankton or group Acritarcha Evitt 1963. Theyhave been divided, mostly on vesicle shape,into a number of informal subgroups, includingthose proposed by Downie, Evitt and Sarjeantin 1963. This system of subdivision is nowseen as less than satisfactory, as there are anumber of gradational forms betweensubgroups, particularly in forms with processesbetween spherical and polygonal vesicles.None of the subdivision schemes for theacritarchs is entirely satisfactory, so manyresearch workers currently list all theacritarchs, algal cysts, colonial algae,chlorophyta (chorophyceae), and prasinophyta(prasinophyceae) together alphabetically whendescribing Palaeozoic palynological

assemblages. In the Mesozoic and Cenozoicthey are sometimes treated together with thedinoflagellate cysts as part of the organic-walled phytoplankton.

The following classification refers to subgroupsand other groupings that may provide progresstowards a more natural classification. Thethreefold division of acritarchs withoutprocesses or flanges, acritarchs with flanges(but no processes), and acritarchs withprocesses (with or without flanges) is based onthe basic subdivision adopted in the FossilRecord 2 (Dorning, 1993)

Division 1. Acritarchs without processes orflanges.This category includes the subgroupSphaeromorphitae, the sphaeromorphacritarchs, together with the Schizomorphitae,Scutellomorphitae and Navifusa group. Thegrouping is almost certainly polyphyletic, andincludes forms that could belong to the greenalgal groups Chlorophyta (Chlorophyceae) andPrasinophyta (Prasinophyceae). Some formswith an indistinct wall may be related to theCyanophyta (cyanobacteria; blue-green algae).The first organisms that could be seen asacritarchs date from around 3800Ma, but theseshould probably be considered to beCyanophyta, with the first sphaeromorphacritarchs 20-200 um in diameter known fromaround 1800Ma, following on from the rise inoxygen levels in the atmosphere. Thesphaeromorph acritarchs have a longcontinuous record through the latePrecambrian, Palaeozoic, Mesozoic andCenozoic and continue though the Holocene tothe present day. Some spheromorphacritarchs, including forms referable toLeiosphaeridia Eisenack 1958 andLophosphaeridium Timofeev 1959 ex Downie1963, occur in abundance in apparentlyfreshwater palaeo-environments, as well asshallow shelf to open ocean environments. Theinclusion of the sphaeromorph acritarchs within

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the informal group Cryptarcha has not beengenerally adopted. The distinction betweensome thick walled sphaeromorph acritarchs,cryptospores and thin alete plant spores canbe difficult in some Palaeozoic palynologicalassemblages.

The Navifusa group of elongate acritarchs,includes NavifusaCombaz et al. 1967, a marine form in theOrdovician to Silurian, and Quisquilites Wilsonand Urban 1963, a possible non marine form,in the Devonian.

The Moyeria group includes the discoidalacritarchs Moyeria Thusu 1973, ChomotriletesNaumova 1939 and Concentricystes Rossignol1962 ex Jansonius and Hills 1976, acritarchsof apparent terrestrial or fluvial affinity that maypossibly have affinities with the Euglenophytaor Prasinophyta.

Division 2. Acritarchs with flanges, butwithout processes.This category includes many forms in thesubgroups Herkomorphitae (herkomorphacritarchs) and Pteromorphitae (pteromorphacritarchs). Some species attributed toCymatiosphaera O.Wetzel 1933 ex Deflandre1954, Dictyotidium Eisenack 1955 andPterospermella E isenack 1972 (+Pterospermopsis W.Wetzel 1952) are clearlyrelated to the Prasinophyta, while others are ofuncertain affinity. The cysts or phycoma(phycomata) of many prasinophytes arephotosynthetic and therefore planktonic, whichmay explain their wide distribution in themarine realm in sediments depositednearshore, across shelf seas to the openocean. The size of individuals within manyspecies of Cymatiosphaera and Dictyotidium isoften rather variable, making consistentspecies identification difficult.

The Cymatiosphaera group, with manyfields, includes C y m a t i o s p h a e r a andDictyotidium.

The Pterospermella group, with a singleequatorial flange, includes Pterospermella andPterospermopsis.

Division 3. Acritarchs with processes, withor without flanges.This category includes many forms in thesubgroups Acanthomorphitae (acanthomorpha c r i t a r c h s ) , C o r y p h o m o r p h i t a e ,Diacromorphitae (diacrodian acritarchs),

Netromorphitae (netromorph acritarchs),Oomorphi tae (oomorph acr i tarchs) ,Po lygonomorph i tae (po lygonomorphacr i ta rchs) and Pr ismatomorph i tae(prismatomorph acritarchs). Some very largeforms with rigid processes, originally describedas acritarchs, may have affinities with themasuelloids (Muellerisphaerida), planktoniczooplankton with an organic and phosphatewall that are mostly found in Palaeozoic deepwater oceanic sediments.Several groupings can be recognised inacritarchs with processes, based on the vesicleand process wall structure and ornament,process style and excystment method. Thesegroupings, used with care, are likely to beparticularly useful in palaeoenvironmentalinterpretations. Some of these groupings havebeen recorded in Downie 1973 and Dorningand Bell 1987.

Acanthodiacrodium group. This group ischaracterised by a simple wall structure andelongate body shape. The group, whichincludes Acanthodiacrodium Timofeev 1958 isparticularly abundant in the late Cambrian toearly Ordovician, where it grades into formswith four corners, of which some areattributable to Coryphidium Vavrdová 1972.

Ammonidium group. This group has anexcystment structure that divides the vesicleinto two equal halves. Salopidium Dorning1981, Ammonidium Lister 1970 andGracilisphaeridium Eisenack and Cramer inEisenack et al. 1973 show increasing processcomplexity. The Si lur ian acr i tarchsH e l o s p h a e r i d i u m Lister 1970 andPercultisphaera Lister 1970 have a similarexcystment mechanism.

Cymatiogalea group (galeate acritarchs)This group is characterised by a largecyclopyle as found in Caldariola Molyneux inMolyneux and Rushton 1988, CymatiogaleaDeunff 1961, Priscogalea Deunff 1961 andSte l l i fer id ium Deunff et al. 1974 and ischaracteristic of the early Ordovician.

Diexallophasis group. This group, whichincludes Diexallophasis Loeblich 1970, EvittiaBrito 1968 and Tylotopalla Loeblich 1970 ischaracterised by an irregular echinateornament. A few species are found in the lateOrdovician, but it is a common component ofthe Silurian and Devonian assemblages.

D o m a s i a group. This group of smallacritarchs with a simple wall and low number of

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processes of variable length includes DeunffiaDownie 1961 and Domasia Downie 1961. It isabundant in the late Llandovery to earlyWenlock of the Welsh Basin (eastern Avalonia)and parts of eastern North America.

Dilatisphaera group. Dilatisphaera Lister1970 is unusual in having thin tubularprocesses that open distally. The wallcomposition is different from most acritarchs inthat it is reluctant to take the regressive redSafranin stain.

Duvernaysphaera group. This group, whichincludes DuvernaysphaeraStaplin 1961and Quadraditum Cramer 1964,has an equatorial flange supported byprocesses. It is possible that the equatorialflange would suggest that this group could beincluded in the prasinophyta.

Eisenackidium group. This group with adouble vesicle wall and a thin flexible processwall includes Eisenackidium Cramer and Díez1968 ex Eisenack et al. 1973 with simpleprocesses, and Leptobrachion Dorning 1981with branched processes.

Eupoikilofusa group. This group of largeelongate acritarchs includes EupoikilofusaCramer 1970 and large forms of LeiofusaEisenack 1938. It is commonly recorded in theSilurian and Devonian.

Estiastra group. These are very largeacritarchs with a very thin wall, sometimes withdark blotches, which includes EstiastraEisenack 1959, Hogklintia Dorning 1981 (=H o e g k l i n t i a Dorning 1981) andPulvinosphaeridium Eisenack 1954. They areonly found in late Ordovician to Silurian tropicalcarbonate environments. Their large sizetogether with an apparently different wallcomposition suggests that they might not becysts of planktonic algae, though there is littleevidence to relate them to benthonic algae aspreviously suggested by Dorning 1981.

Micrhystridium – Veryhachium group.This is a large group of small acritarchs with asimple wall and simple processes. The group,which includes some, but not all speciescurrently attributed to Micrhystridium Deflandre1937 and Veryhachium Deunff 1954, togetherwith small forms of LeiofusaEisenack 1938, is long ranging from the latestPrecambrian, through Palaeozoic andMesozoic to Tertiary. Representatives of thisgroup are the main acritarchs with processes

in the Permian, Triassic, Jurassic, Cretaceousand Cenozoic.

Onondagella group. This group has threedifferent processes and a wall that is reluctantto take regressive stains, including Safrannin.Onondagella Cramer 1966 is possibly related to thechlorophyta, given that four specimens couldbe arranged to form a tetrahedral colonysimilar to Deflandrastrum Combaz 1962,though, to my knowledge, this has never beenobserved.

Oppilatala group. This grouping has a largegape excystment opening and includesOppilatala Loeblich and Wicander 1976 andsome species currently attributed toDateriocradus Tappan and Loeblich 1971.

Orthosphaeridium group. This group withplugged bases to the processes and a straightsplit as an excystment opening includesBacisphaeridium Eisenack 1962 andOrthosphaeridium Eisenack 1968.Tunisphaeridium group. This group with solidwire-like processes includes CarminellaCramer 1968, Elektoriskos Loeblich 1970,Geron Cramer 1966 ex Cramer 1969 andTunisphaeridium Deunff and Evitt 1968.

Visbysphaera group. This group normallyhas a double walled vesicle and numerousheteromorphic processes. Specimens withoutthe inner wall are often observed. The groupincludes Psenotopus Tappan and Loeblich1971 and Visbysphaera Lister 1970.

References.A list of taxonomic references may be found inMullins, Aldridge and Dorning 2004.CIMP Acritarch Subcommission (from 1986).Acr i ta rch News le t te r . Commiss ionInternationale de Microflore du Palaeozoique,http://www.shef.ac.uk/~cidmdp/archnews.html#acDorning, K.J. 1981. Silurian acritarchs from thetype Wenlock and Ludlow of Shropshire,England. Review of Palaeobotany andPalynology, 34, 175-203.Dorning, K.J. 1993. Group (‘Phylum’)Acritarcha Evitt, 1963 In: Benton M.J. (ed) TheFossil Record 2, pp 33-35, Chapman and Hall,London.Dorning, K.J. 2004. Acritarchs in Selley, R.C.,Cocks, L.R.M. and Plimer, I.R. (eds)Encyclopedia of Geology, Elsevier, Oxford, vol.3, 418-427. ISBN: 0126363803.

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Dorning, K. J. and Bell, D. G. 1987. TheSilurian carbonate shelf microflora: acritarchdistribution in the Much Wenlock LimestoneFormation. In. J. W. Neale and M. D. Brasier(eds). Microfossils from Recent and FossilShelf Seas, p. 265-287. Ellis Horwood,Chichester.Downie, C. 1973. Observations on the natureof the acritarchs. Palaeontology, 16, 239-259,pl. 24-27.Downie, C., Evitt, W. R. and Sarjeant, W. A. S.1963. Dinoflagellates, hystricho-spheres, andthe classification of the acritarchs. StanfordUniversity Publications, Geological Sciences,7, p. 1-16.Evitt, W. R. 1963. A discussion and proposalsconce rn ing foss i l d ino f l age l l a tes ,hystrichospheres, and acritarchs. Proceedingsof the National Academy of Sciences of theUnited States of America, v. 49, p. 158-164.Mullins, G.L., Aldridge, R.J. and Dorning, K.J.2004. The phytoPal reference database,0 9 / 0 9 / 2 0 0 4 , 9 7 p p .http://www.le.ac.uk/geology/glm2/phytopal/reference_database.pdf

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NEWS FROM ACRITARCH WORKERS

Roberto Albani (albani@dst.unipi.it)

Dipartimento di Scienze della Terra, Universitàdi Pisa, via Santa Maria 53, 56126 PISA –Italy. Tel. 0039 050 847 239; Fax 0039 050847 300.

The group of Pisa (Albani, Bagnoli e Ribecai)is actively working on taxonomy andpaleobiogeography of palynomorfs from theCambrian-Ordovician successions of Spainand the island of Öland (Sweden).Spain – Research continues on Cambrian andOrdovician successions of the Laviana andRioseco thrust sheets, Cantabrian Zone,northern Spain (“Túnel Ordocvícico delFabar”). It has been completed the study of theCambrian acritarch association recovered inthe tunnel and a paper is in press. Specialattention has been paid to the genus Lusatiaand a work on its morphological variability,taxonomy, biostratigraphical significance, andpaleobiogeographical distribution is in progressin cooperation with Elena Raevskaya. Futureresearch will focus on acritarchs andassociated chitinozoans of the Ordoviciansuccession.Öland - Taxonomical studies of petenoidacritarch genera and associated chitinozoansacross the Volkov/Kunda boundary are inprogress. The succession of acritarch speciesis compared with available data on conodontbiostratigraphy and biofacies, and sea-levelchanges. Future research will be devoted tothe other acritarch genera present in the Ölandsequences

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Ken J. Dorning,(k.j.dorning@sheffield.ac.uk)

Pallab Research, 58 Robertson Road,Sheffield S6 5DX, England

http://www.shef.ac.uk/uni/academic/ N-Q/palysc/Palystaf/dorning.html

Research continues on acritarchs andchitinozoans, with emphasis on the distributionpatterns related to stratigraphy andpalaeoenvironmental distribution. Wellpreserved acritarchs, chitinozoans and otherpalynomorphs are being examined fromsamples collected throughout the late Gorstianand Ludfordian succession from WoodburyQuarry, NGR SO743637 Worcestershire,England. New information from the lateLlandovery and Wenlock from Shropshire isbeing brought together for publication incollaboration with Craig Harvey and JaneWashington-Evans. The acritarch abundancedata from the late Cambrian to earlyOrdovician from eastern Avalonia is beingsynthesized, in collaboration with GarethHughes.I have spent some time gathering togetherinformation for the phytoPal project, funded bythe Leverhulme Trust, which aims to documentthe global and stratigraphical distribution of thePalaeozoic phytoplankton. I have completedthe species that I have previously described,and am now working through the acritarchspecies with type material housed in thepalynological collections housed at theUniversity of Sheffield.

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----------------------------------------------------

Kath Grey(kath.grey@doir.wa.gov.au)

37 Harris Street, Carlisle, 6101, WA -AUSTRALIAMail address: Geological Survey of WesternAustralia, Department of Industry andResources, 100 Plain Street, East Perth WA6004 AUSTRALIAPhone: +61 08 9470 0302Fax: +61 08 9362 5694

I spent a lot of time this year revising mymonograph on the Ediacaran (lateNeoproterozoic) palynology of Australia. It wasreturned to the editor for final checking at theend of December, and should be published inthe Aus t ra las ian Assoc ia t ion o fPalaeontologists Memoirs series, probably inmid-2005. It has been difficult to find the timeto work on the monograph with all the otherprojects that are on my desk, and it hasrequired constant updates to keep it in line witha fast moving area of research. Work byEmmanuelle Javaux of the University of Liègeand Craig Marshall of Macquarie University onbiomarkers from individual specimenssuggests that the large acanthomorphacritarchs were probably a unique and short-lived group of algae. The distinctive speciesTanarium conoideum (=Hocosphaeridiumscaberfaceum Zang and Walter 1992) hasbeen recorded from three tectonic units inAustralia, and it is present in China andSiberia. Although several palaeobiologistshave suggested that these acanthomorphscould be a protist eggs or embryos, thepresence of algaenan suggests that they aremore likely green algae. The evidenceobtained to date suggests that Tanar iumconoideum will be a key marker fossil globallyfor the middle Ediacaran. However, there areobvious disparities between the Chinese andAustralian successions that need to beresolved before the zonal scheme for Australiacan be more widely adopted.

A visit to Europe in mid-2004 allowed me tocatch up with Malgorzata Moczydlowska andSebastian Willman at Uppsala University. Theyare continuing the work on the Ediacaranacritarchs and their possible relationship to the

Acraman event using a more refined samplingstrategy and are looking at drillholes that I wasunable to examine in detail. Their preliminarywork seems to follow the patterns I had alreadyobserved, and we are in the process ofpreparing a couple of manuscripts on the latestfindings and their significance. Andrew Hill ofMacquarie University continues his studies ofthe chemostratigraphy across the Acramaninterval. I presented a talk summarisingprogress, particularly on the biostratigraphicaspects, at the Palynological Congress inGranada and one on the possible relationshipof the rapid diversification of the palynofloraand the Acraman impact event at theGeological Society of America Annual Meetingin Denver in November.

Work also continues on documenting thePrecambrian biostratigraphy of WesternAustralia, using palynology and stromatolites,and in particular, the taxa present in a new drillcore, GSWA Lancer 1 from the Officer Basin.Preliminary studies indicate that the samestromatolites and palynological assemblagesseen in Empress 1 and 1A are present.Results have confirmed the significance of theornamented acritarch, Cerebrosphaera buickiias a key index fossil for the Cryogenian atabout 750 Ma Australia-wide. I have also beencontinuing studies of various Archaeanstructures.

Reference

JAVAUX, E.J., MARSHALL, C.P., KNOLL, A.H. &WALTER, M.R., 2004. Protistan evolution in thePrecambrian: a new multidisciplinary approachcombining microscopy and microchemistry.Geological Society of America, Abstracts withPrograms 36, 399.

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Li, Jun (junli@nigpas.ac.cn)

Nanj ing Inst i tute of Geology andPalaeontology, Chinese Academy of Science,Nanjing, 210008, China. Tel(+)86 2583282153; Fax: (+) 86 25 83357026.

I continue working on Ordovician acritarchsfrom China. In July, I went to Granada, Spainfor XI IPC, participating in the Lower

23

Palaeozoic palynology/CIMP symposiumwhere I gave a talk. I then spent one month inLille, France, working with Thomas Servais onOrdovician acritarchs from South China. FromSeptember 1-12, I participated in the openingmeeting of IGCP 503 (Early PalaeozoicPalaeogeography and Palaeoclimate) inErlangen, Germany, and gave a talk. This wasfollowed by the post-conference field trip inOland and Gotland, Swenden. FromSeptember 20 to December 14, I am at CentralMichigan University, Mount Pleasant, USAworking with Reed Wicander on UpperOrdovician acritarchs from Tarim, China. GaryMullins joins us in the 2-10th/Nov. to discussthe Phytopal project. In June my MsC studentYAN Kui submitted his master thesis:Biostratigraphy and biodiversity of Ordovicianacritarchs from Meitan Formation of TongziCounty, Guizhou Province, South China. InSeptember, 2004, YAN Kui received a PhDgrant to continue working on acritarchs for thenext three years in Nanjing.

----------------------------------------------------

Yan Kui (ykyankui@yahoo.com.cn)

Nanjing Institute of Geology and Palaentology,Chinese Academy of Sciences, Nanjing210008, China. Tel.: +86-25-83282148; Fax:+86 25 83357026.

I am a PhD student, supervised by Dr. Li Jun. Ihave studied on Ordovician acritarchs fromSouth China for three years, and submitted mymaster thesis: Biostratigraphy and biodiversityof Ordovician acritarchs from Meitan Formationof Tongzi County, Guizhou Province, SouthChina this summer.In the next three years, I will continue workingon Ordovician acritarchs from South China, formy PhD Thesis. In November 2nd to 21st , Idid field work in Yichang to collect samplesfrom Ordovician strata.

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Alain Le Hérissé (alain.le.herisse@univ-brest.fr)

Laboratoire de Paléontologie, UMR 6538 duCNRS "Domaines Océaniques", Université de

Bretagne Occidentale, 6, Av. Le Gorgeu BP809, Brest, France.

My interest in 2004 has been concentrated ontwo major aspects: the late Ordovicianpalynological signal (Algeria, northern Chad,South Libya, etc.), and a sound revision of thestratigraphic evolution of the acritarchs andother microalgae assemblages in the Devonianof North Africa and South America. Incomplement detailed studies on Silurianassemblages and relationships with eventscontinue, particularly using the "key" materialof Gotland. Academic activities are completelymixed with commercial applications andexpertises, where it appears that a goodsystematic and biostratigraphy remains veryappreciated. Intriguing aspects of organicsedimentation (marine and continental),m ic rogeochemis t r y and pa r t i cu la rconcentrations of microphytoplankton have also been studied in collaboration with otherscolleagues (Lena Raevskaya, EmmanuelleJavaux, Philippe Steemans, Marco Vecoli ....).2004 has seen publication of a big synthesison the study of Ordovician acritarch diversitywith Marco Vecoli in Earth Sciences Review. Imentionned also here another reference inMarine and Petroleum Geology (note of editor :see list of acritarch publications, 2004 below ).Brest, "City of the Sea" stays a center ofFormation for Palynology, particularly for thePaleozoic : Miguel Perez Leyton is working onthe Devonian Palynostratigraphy of Bolivia(PHD  In cotutelle with Liege and P.Steemans); Benson Modie is completing aPHD on the Palynostratigraphy of the Permianof Botswana.

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Malgorzata Moczydlowska-Vidal(malgo.vidal@pal.uu.se)

Uppsala University, Department of EarthSciences, PalaeobiologyNorbyvägen 22, S-752 36 Uppsala, SWEDEN.Tel: + 46 18 471 27 43 ; FAX: + 46 18 471 2749

http://www.paleobiologi.geo.uu.se

Two Ph.D. projects and two M.Sc. projectsdealing with microfossils are on the way and

24

supervised by M.Moczydlowska.Martin Stockfors works on his Ph.D. project onRadiation and extinction trends of Cambrianphytoplankton and he presented the Licentiatthesis last year (2003) on Late Cambrian-EarlyOrdovician acritarchs from Kolguev Island,Arctic Russia: biodiversity, global correlationand palaeoge-ographic reconstruction. Hecontinues at the moment the study on materialsomewhat different from acritarchs, andphytoplankton in general, but exciting and new,and this is the record of endolithiccyanobacteria from the Middle Cambrian ofNorth Greenland. Martin is going to defend histhesis next year (2005).Sebastian Willman began his Ph.D. project in2003, so it is just a first year of research, onOrigins of Neopro-terozoic-Early PalaeozoicPhyto-plankton. He studies the Ediacaran largeacritarchs from Australia, which derive fromsubsurface successions in the Officer Basinand represent the first distintive radiation ofphytoplankton in Neoproterozoic. Theappearance of ca. 50 new taxa (genera andspecies) preceds the radiation of the Ediacara-type metazoans and it has happened in theaftermath of the deglaciation and globalclimatic change following the Snowball Earth.Sebastian presented his initial results at theGranada congress.M.Sc. thesisMette Jergensson studies the cyst formationand life cycle of Recent prasinophycean algaewith reference to the early Ordoviciancollection of very well-preserved Saharidiafragilis from the Kolguev Island, Arctic Russia.She is at the moment on mother-leavebecause of her new-born baby, but willcontinue soon and present her thesis at thebeginning of 2005.Petrus Lindh is finishing his M.Sc. work onMiddle Jurassic benthic foraminifera from theJura Mountains, France, and their bearing onbiofacies recognition.M. Moczydlowska is continuing her researchon Neoproterozoic and Cambrian acritarchbiodiversity based on new collections fromArctic Russia, China and Australia incollaboration with Kathleen Grey (GeologicalSurvey of Western Australia, Perth), YinLeiming (Nanjing Institute of Geology andPaleontology, Academia Sinica), and WenlongZang (Geological Survey of South Australia,Adelaide). The new projects for the next 3-4

years are on Neoproterozoic microbialdiversification - a prelude to the Phanerozoicworld (M.M. principal investigator incollaboration with A. Knoll, K. Grey), andGlobal biogeochemical cycles and early animalevolution, as invited investigator to join theteam of A.H. Knoll (Harvard University) andR.E. Summons (MIT).M. Moczydlowska and T. Palacios (Badajoz)organised the Pre-Cambrianpalynology/CIMP Symposium at the 11thInternational Palynological Congress,4-9 July 2004, Granada, Spain. This was thefirst time organised session onorganic-walled microfossils from Proterozoic atthe Palynological Congress forum and at suchoccasion not very numerous researcherscontributed with the talks (five speakers; withthe change of the published programme:Sebastian Willman instead of Yin Leiming etal.,). The session attracted a good audienceand it was well-received. M.Moczydlowska andS. Willman from our group in Uppsalapresented oral presentations.M. Moczydlowska is from 2004 the 1st Vice-Chairperson of the IUGS, ICS, InternationalSubcommission on Cambrian Stratigraphy.Following the 32nd International GeologicalCongress, Florence - Italy, August 20-28,2004, the ISCS executive is a s follows:

Chairman: S. Peng, Nanjing, China.Secretary: L.E. Babcock, Columbus, OH,U.S.A.1st Vice-Chairperson M. Moczy-dlowska,Uppsala, Sweden2nd Vice-Chairperson G. Geyer, Wurzburg,Germany.The forthcoming meetings of the CambrianWorking Group are:Fourth International Symposium on theCambrian System 2005 in Nanjing, China: seecirculars on the website:

www.nigpas.ac.cn/cambrian-conference/index.htm)

Cambrian Subdivision Working Group FieldConference 2006 in the easternU.S. Forthcoming information on the website:

www.uni-wuerzburg.de/palaeontologie/ISCS/index.htm)

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----------------------------------------------------

Gary Mullins (glm2@leicester.ac.uk)

Department of Geology, University ofLeicester, University Road, Leicester LE1 7RH,United Kingdom. Tel: +44 (0)116 2523924;Fax: +44 (0)116 252 3918.

I have been continuing to create a database oftaxa for the phytoPal project, which aims todocument the d ive rs i t y o f themicrophytoplankton from the Late Precambrianto the Triassic. This database now contains therecords of 900 genera and 5300 species and Iam including detailed taxonomic information(e.g. previous generic assignments,synonymies and diagnoses) and data on thestratigraphical range of each taxon. Thestratigraphical ranges are being checked bymyself and by the other partners in the project(Dick Aldridge, Ken Dorning, Alain Le Hérissé ,Malgorzata Moczydlowska-Vidal, StewartMolyneux, Thomas Servais and ReedWicander). We intend to present a diversitycurve for the Lower Palaeozoicmicrophytoplankton at the AASP meeting in St.Louis in September 2005. I have alsocontinued to create a list of publications onprincipally Palaeozoic microphytoplankton,which can be downloaded from the phytoPalwebpages at

http://www.le.ac.uk/geology/glm2/phytopal.html

This list is by no means complete and thesubmission of new references is alwayswelcome.

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Leonard Olaru (lola@uaic.ro)

University "Al.I.Cuza" Iasi, Department ofGeology, Bd.Carol the 1-st, 20 A, Iasi, 700 505Romania.   

My researches in 2004 were focused onacritarch and chitinozoan studies from themetamorphic formations of the  EastCarpathians of Romania in order to propose abiozonation for these deposits. In addition, I supervised and collaborated with my

Ph.D. students on palynological researches ofthe Palaeozoic and Tertiary Deposits ofRomania. The Thesis on the Tertiary Depositsis now complete, with the title : " Palynologyand  biostratigraphy of the Lower MioceneDeposits and a associated bituminies from theSlanic -Oituz Half-window, EasternCarpathians, Romania", by Geol. eng.Alexandru Stoicescu, Moinesti  PetroleumCompany. From the October,1, I retired, but Icontinue to work in the Geological Department,as Consulting Professor, supervising Ph.D.students.

Interesting forth-coming scientific events for usare the 5-th Symposium of Palaeontological Society of Romania, to be hold in Bucharest,September 2005, and our  Scientific Session ofGeological Department of the University"Al.I.Cuza" Iasi  (October,2005), which is heldevery year around October ,26, CelebrationDay of the University.

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Claudia Rubinstein(crubinstein@arlinkbbt.com.ar)

IANIGLA -CRICYT C.C. 131 5500 – Mendoza,Argentina. Tel: +54 261 4287029/4274011;Fax: +54 261 4285940.

I continue working on biostratigraphy,paleobiogeography and paleo-environments ofPaleozoic palyno-morphs (acritarchs,chitinozoans and miospores) from Argentinaand South America.Current research involves:• The Ordovician and Silurian of the Central

Andean Basin, north-western Argentina,particularly focused on the Cambrian/Ordovician, Tremadoc/Arenig and theOrdovician/Si lur ian boundaries, theOrdovician radiation, the effects of the lateOrdovician glaciation and the Silurianbiodiversification.

• The lower-middle Ordovician volcanic arc ofFamatina, northwestern Argentina.

• The Ordovician to Devonian palynology of thePrecordillera Basin, in collaboration withPhilippe Steemans

• The Silurian/Devonian boundary of Brazil incollaboration with Philippe Steemans andAlain Le Hérissé.

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• The Devonian/Carboniferous boundary innorthern Chile.

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Thomas Servais (thomas.servais@univ-lille1.fr)

Paleontologie - Sciences de la Terre, UMR8014 CNRS, Cité Scientifique SN5, F-59655Villeneuve d'Ascq Cedex – FRANCE. Tel:(+33) (0)3 20 33 72 20; Fax:(+33) (0)3 20 4369 00.

I continue research focused on Ordovicianacritarchs, with some excursions to theCambrian and Silurian (but also the Permian),and some excursions to other fossil groups(such as carbonate microfossils, ...).Elena Raevskaya (St. Petersburg, Russia)spent ten months in our department at Lille(October 2003 to August 2004), and weworked together on the Tremadoc/Arenigboundary (with S. Molyneux, BGS, UK) and onsome Late Cambrian diacrodian acritarchs,such as V. dumontii and related forms. A MScstudent (Mathilde Blanchon) worked on acomplete rev is ion o f the genusVu lcan isphaera , a work that should beprepared for publication in the next year. TheIGCP 410 (The Great OrdovicianBiodiversification) book was published, butthere is still a lot of work to do before weunderstand the biodiversification of themicrophyto-plankton. This can now be donewith Marco Vecoli (who is now at Lille too)within the PhytoPal working group. The specialissue in the Review of Palaeobotany andPalynology, serving as proceedings volume ofthe CIMP meeting of September 2002, waspublished, and the next special issue (basedon papers presented at the IPC) is now inprogress (I am guest-editing this together withMarco).2004 was an (extremely) busy year with theorganisation of a series of conferences.Scheduling the CIMP session on LowerPalaeozoic at the IPC at Granada (early July)took some time, as well as the organisation ofthe new IGCP n° 503 (OrdovicianPalaeogeography and Palaeoclimate) and itsofficial opening meeting at Erlangen, Germany( e a r l y S e p t e m b e r ) m u c h m o r e(http://www.pal.uni-erlangen.de/IGCP503/).

Finally, the last part of the year was a disasterperiod with the organisation of the 48th AnnualMeeting of the Palaeontological Association(mid December), and the associated PhytoPalworkshop (with Gary Mullins). All these eventswere highly successful but took a lot of time foradministration (and less work on themicroscope). Thus, 2005 could be a good yearto return to some basic scientific work.

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Paul Strother (strother@bc.edu)

Palæobotanical LaboratoryWeston Observatory of Boston CollegeDepartment of Geology & Geophysics,381 Concord RoadWeston, Massachusetts 02493 UStel 617 552-8395, fax 617 552-8388 .

Acritarch Research Update (3 projects):

1) In the Palæobotany Laboratory at WestonObservatory we are beginning to look throughseveral cores from the Silurian of WestVirginia, US. They represent more distal faciesfrom the cryptospore-bearing units that wehave worked on from Pennsylvania andVirginia. The cores were sampled in 2003 withCharles Wellman and the samples wereprocessed at Sheffield. The most interestingresult to date is that the subsurface, TuscaroraFormation in West Virginia is almostcompletely lacking cryptospores in its mudrockintervals, but is quite rich in acritarchs. We maybe able to document a transgressivedepositional sequence through the Aeronian-Telychian interval. It will be interesting to see ifthe taxon distribution in the distal Tuscaroramatches overlying marine shales in the moreproximal setting to the east.2) We have begun a project to tabulate andassess Middle Cambrian acritarchs from theLaurentian margin within the US. These are allbyproducts of work on proximal facies that arerich in non-marine elements. Middle Cambriandeposits are characterized by rare (ca. 1% oncount) very smal l acanthomorphs,Lophosphaeridium, and Dictyotidium-likespecimens. The specimens are typically verysmall, 8 to 12 µm, and there is probably someoverlap with an assemblage being describedfrom the Burgess Shale by Kevin Gostlin at the

27

University of Toronto. Samples from the upperCambrian of the Western United States containthermally immature monospecific assemblagesof Polygonium which are of normal size. It isnot clear whether this Lilliputian MiddleCambrian world is facies controlled, or if thereis a world-wide trend toward small acritarchsduring this interval.3) Lastly, a proposal to NSF for examining theLate Devonian acritarch decline has been itselfdeclined, but we will be collecting more datafrom the upper Devonian of New York State tolook at this question. This project is inconjunction with Charles verStraeten, astratigrapher who works for New York State.

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Marco Vecoli (marco.vecoli@univ-lille1.fr)

Lab. de Paléontologie et Paléogéographie duPaléozoique, UMR 8014 CNRS, CitéScientifique SN5, F-59655 Villeneuve d'AscqCedex – FRANCE. Tel: (+33) (0)3 20 43 41 36;Fax:(+33) (0)3 20 43 69 00.

In October, 2004 I have been appointed“Chargè de Recherche” at the French CNRS,so I am finally enjoying a permanent position ina research institution.The job-searching job during 2004 took most ofmy time, but I was nonetheless able todedicate some “spare time” between oneinterview and the other, to research as well assome minor consulting jobs.I have mostly been studying an interestingpalynological assemblage from the SaudiArabian Llanvirn, which comprises acritarchs,chitinozoans, and cryptospores. This work wasdone in collaboration with Alain Le Hérissé(CNRS Brest) and Monsour Al-Ruwaili (SaudiAramco, Dahran); we presented a talk at theIPC in Granada, and a first publication is inprogress about that.During the first part of 2004 I also collaboratedwith Alain Le Hérissé for a consulting jobcommitted by the company Gas de France forthe biostratigraphic dating of Palaeozoic clasticsequences in Algeria.From March to August 2004 I was postdoc inLille; as I said, I used most of this time for job-applications, but I also worked together withOliver Lehnert (Univ. of Erlangen, Germany)on the problem of the causes of the “Great

Ordovician Biodiversification Event”. Weapproached this study mostly in relation withthe question of the significance andinterpretation of the record of acritarch diversityand abundance in terms of oceanic primaryproduction. A paper on the subject (also incollaboration with Thomas Servais, CNRSLille) is currently in progress, and we willpresent a talk at the next meeting of theEuropen Geoscience Union in Vienna nextApril.Currently, I am working on the revision ofpalynological material from the Sud Alpinebasement, Italian Alps in order to try toelucidate the depositional age of themetamorphic basement in the Eastern Alps.This work is done in collaboration with Prof.Iginio Dieni and Prof. Francesco Sassi of theUniversity of Padova, Italy.Since October, I have been occupied with thesetting up of a new palynological laboratory inLille, since the existing laboratories were notoperational anymore. Now all the necessaryworks have been completed and brand newequipment is in place; the lab is fullyoperational and we expect a good flux ofpalynological preparations to go through.For the next future, I am going to start a newproject based chiefly on cryptospores andmiospores, aiming at the study of the processof the invasion of emerged lands by theearliest plants during Ordovician throughDevonian times (“terrestrialization”), and theassociated global changes. An integratedpalynological – sedimentological – geoche-mical approach will be utilized. During the lastpart of 2004 I have been working on gatheringsuitable material for this project. I have comeinto possession of about 300 samples fromseveral subsurface sections in North Africa; inthis, I was helped by Florentin Paris (CNRSRennes) and Dominique Massa (formergeologist at Total; Paris). At the moment, I amslowly starting the study of a couple of lateSilurian – early Devonian sections in Algeria, incollaboration with Florentin Paris. Field workand further core-sample collecting from NorthAmerican sections is being organized with PaulStrother (Weston observatory, Boston, U.S.A.).Together with Enrique Diaz-Martinez (principalInvestigator; Univ. of Madrid, Spain), we havesubmitted, to the evaluation of the EuropenCommission in the framework of the 6th

framework programme, a research proposal

28

entitled: Sedimentary record of climatechanges in the Palaeozoic of the CentralAndes.I am also a partner in two large projectsfocused on the late Ordovician glaciation: theECLIPSE project, funded by the French CNRS(project leader Jean François Ghienne, CNRSStrasbourg, France), and a further project ledby Enrique Villas and Javier Alvaro (both fromthe University of Zaragoza, Spain).Last but not least, all my palynologicalactivities are relevant and contribute to the“Phytopal project” (see p. X), to which Icollaborate since 2003.

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Reed Wicander (reed.wicander@cmich.edu)

Department of Geology, Central MichiganUniversity. Mt. Pleasant, MI 48859 USAPh.: (989) 774-3179Fax: (989) 774-2142

I am continuing my work on Ordovician(Michigan and Australia) and Devonian(Ontario, Canada) acritarchs. At the LowerPaleozoic palynology/CIMP Symposium of theXI IPC this past summer in Granada, Spain, Ipresented the results of the joint study GeoffPlayford and I conducted on the acritarchs andprasinophytes from the Upper OrdovicianSylvan Shale, Oklahoma. The manuscript onthis beautifully preserved assemblage hasbeen reviewed and submitted for publication asa Bulletin of the Oklahoma Geological Survey.I was a coauthor with Huaicheng Zhu from theNanjing Institute of Geology and Palaeontologyon a paper that was also presented at the XIIPC on the Middle Devonian palynomorphsfrom the Junggar Basin, North Xinjiang, China,which was the result of a joint acritarch andspore study we conducted during his 2003 visitwith me at CMU.

Jun Li from the Nanjing Institute of Geologyand Palaeontology spent three months this fallworking with me on a joint study of an UpperOrdovician acritarch and prasinophyte assem-blage from the Dawangou section in the TarimBasin, China. A manuscript on that study hasbeen submitted for publication. Gary Mullins,Department of Geology, University ofLeicester, also spent two weeks with me in

November reviewing Devonian acritarchtaxonomy as part of the phytoPal projectfunded by the Leverhulme Trust ResearchInterchange Grant.

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ACRITARCH PUBLICATIONS, UPDATE

Michel Vanguestaine sent us a complete list of his publications, dated from1999 and that were not previously reported on the Acritarch Newsletter.

Ahrendt, H., Ribbert, K.-H., Vanguestaine, M., Wemmer, K., 2001.K-Ar and acritarch dating of phyllite clasts from a resedimented Middle Devonianconglomerate in the northwestern part of the Rhenish Slate Mountains. Zeitschr.deutsche geologische Ges. 152/2-4, 365-377.

Boulvain, F., Bultynck, P., Coen, M., Coen-Aubert, M., Lacroix, D., Laloux, M.,Casier, J.-G., Dejongue, L., Dumoulin, V., Ghysel, P., Godefroid, J., Helsen, S.,Mouravieff, N.A., Sartenaer, P., Tourneur, F., Vanguestaine, M., 1999.Les Formations du Frasnien de la Belgique. Memoirs of the Geological Survey ofBelgium 44, 1-125.

Breuer, P., Vanguestaine, M., 2004.The latest Tremadocian messaoudensis-trifidum acritarch assemblage from theupper part of the Lierneux Member (Salm Group, Stavelot Inlier, Belgium).Review of Palaeobotany and Palynology 130, 41-58.

Brück, P.M., Higgs, K., Maziane-Serraj, N., Vanguestaine, M., 2001.New palynological data from the Leinster Lower Palaeozoic massif, southeasternIreland, Transactions of the Royal Society of Edinburgh: Earth Sciences 91, 509-514.

Brück, P.M. , Vanguestaine, M., 2004.Acritarchs from the Lower Palaeozoic succession on the south County Wexfordcoast, Ireland : new age constraints for the Cullenstown Formation and theCahore and Ribband Groups. Geological Journal 39 (2), 199-124.

Maziane-Serraj, N., Brück, P.M., Higgs, K., Vanguestaine, M., 1999.Re-evaluation of proposed terranes in the Leinster lower palaeozoic massif inIreland using palynology : some preliminary results. In Fatka, O. and Kraft, P.(ed). Proceedings of 8th International Symposium on the Ordovician System,Prague, June 1999. Acta Universitatis Carolinae, Geologica 43, 241-242.

Maziane-Serraj, N., Brück, P.M., Higgs, K.T., Vanguestaine, M., 2000.Ordovician and Silurian acritarch assemblages from the west Leinster andSlievenamon areas of southeast Ireland. Review of Palaeobotany andPalynology 113, 57-71.

Ribbert, K.-H., Servais, T., Vanguestaine, M., 2002.Stratigraphische Kommission Deutschlands : chap. 4.28 Stavelot-Venn-Antiklinale (28). Courier Forschungsinstitut Senckenberg 235, 68-89.

Sarjeant, W.A.S., Vanguestaine, M., 1999.Maria Lejeune-Carpentier (1910-1995): a memorial. Journal ofMicropalaeontology 18, 137-142.

Streel, M., Vanguestaine, M., Pardo-Trujillo, A., Thomalla, 2000.E. The Frasnian-Famennian boundary sections at Hony and Sinsin (Ardenne,Belgium): new interpretation based on quantitative analysis of palynomorphs,

30

sequence stratigraphy and climatic interpretation. Geologica Belgica 3/3-4, 271-283.

Vanbrabant, Y., Geeninckx, S., Vanguestaine, M., 2003.Analyse structurale et micropaléontologique des Formations d'Aisemont et deLambermont à Lambermont (Nappe de la Vesdre, Belgique). Geologica Belgica 6(3-4), 119-140.

Vanguestaine, M., 2000.Review of the paper: "Cambrian Acritarchs from Upper Silesia, Poland.Biochronology and Tectonic Implications. M. Moczydlowska. Fossil and Strata,40. Scandinavian University Press Oslo, 1998, 121 pp." Palaeogeography,Palaeoclimatology, Palaeoecology 158, 147-148.

Vanguestaine, M., Servais, T., 2002.Early Ordovician acritarchs of the Lierneux Member (Stavelot Inlier, Belgium) :stratigraphy and palaeobiogeography. Bulletin de la Societé Géologique deFrance 173 (6), 561-568.

Vanguestaine, M., 2002.The Late Cambrian acritarch Cristallinium randomense: morphology, taxonomyand stratigraphical extension. Review of Palaeobotany and Palynology 118, 269-285.

Vanguestaine, M., Brück, P.M., Maziane-Serraj, N., Higgs, K.T., 2002.Cambrian Palynology of the Bray Group in County Wicklow and South CountyDublin, Ireland. Review of Palaeobotany and Palynology 120, 53-72.

Vanguestaine, M., Pardo-Trujillo, A., Coen-Aubert, M., Roche, M., Boulvain, F.,1999.Evolution of organic debris and palynomorph preservation in two late middleFrasnian sections, southern Dinant Synclinorium border, Belgium in Tongiorgi, M.& Playford, G. (eds), Studies in Palaeozoic Palynology. Bollettino della SocietàPaleontologica Italiana 38 (2-3), 317-330.

Verniers, J., Herbosch, A., Vanguestaine, M., Geukens, F., Delcambre, B.,Pingot, J.-L., Belanger, I., Hennebert, M., Debacker, T., Sintubin, M., De Vos, W.,2002.Cambrian-Ordovician-Silurian lithostratigraphic units (Belgium). In : Bultynck P. &Dejonghe, L., Eds., Guide to a revised stratigraphic scale of Belgium. GeologicaBelgica 4 (1-2), 5-38.

Vanguestaine, M., Wauthoz, B., 2003.Age et origine des shales ayant servi à la confection des anneaux préhistoriques(second Age du Fer) de Basècles (Belgique). Geologica Belgica 6 (3-4), 141-161.

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ACRITARCH PUBLICATIONS, 2004:

The following are acritarch-related papers published during 2004. As last year,this list results from the communications from the members of our commission,and from some research which I have done on the web. Of course, it is probablyincomplete but the main articles published in the more diffused internationaljournals should be all there.Abstracts and other material not officially pubmlished in refereed journals arelisted separately.

Dorning, K.J., 2004.Acritarchs, in Selley, R.C., Cocks, L.R.M. and Plimer, I.R. (eds) Encyclopedia ofGeology, Elsevier, Oxford, vol. 3, 418-427.

Li, J., Chanqun C., Servais, T., Youhua, Z., 2004.Later Permian acritarchs from Meishan (SE China) in the context of Permianpalaeobiogeography and palaeoecology. Neues Jahrbuch für Geologie undPaläontologie, Monatshefte 2004.

Li, J., Servais, T., Kui, Y., Zhao, H., 2004.A nearshore-offshore trend in the acritarch distribution of the Early-MiddleOrdovician of the Yangtze Platform. Review of Palaeobotany and Palynology 130(1-4), 141-161.

Moczydlowska, M., 2004.Earliest Cambrian putative bacterial nanofossils. Memoirs of the Association ofAustralasian Palaeontologists 29, 1-11.

Moczydlowska, M., Popov, L.E., Stockfors, M., 2004.Upper Cambrian-Ordovician successions overlying Timanian complexes: newevidence of acritarchs and brachiopods from Kolguev Island, Arctic Russia.Geobios 37 (2), 239-251.

Moczydlowska, M., Stockfors, M., 2004.Acritarchs from the Cambrian-Ordovician boundary interval on Kolguev Island,Arctic Russia. Palynology 28, 1-59,

Olaru, L., Apostoae, L., 2004.Arenigian chitinozoans from the Tulghes Group, Upper Formation (Tg.4)  fromBalan zone  , Eastern Carpathians, Romania. Acta Palaeontologica Romaniae ,vol.IV,Cluj-Napoca, Romania.

Olaru, L., Lazar, A.C., 2004.Acritarch assemblage from the Upper Formation of the Tulghes Group (Tg.4)from Balan Zone, Eastern Carpathians,Romania (Analele  stiintifice aleUniversitatii "Al.I.Cuza" Iasi, Geologie, 2004,

Raevskaia, E., Vecoli, M., Bednarczyk, W., Tongiorgi, M., 2004.Early Arenig acritarchs from the East European Craton and theirpalaeobiogeographic significance. Lethaia 37 (1), 97-111.

Rubinstein, C. V., Mángano, M.G., Buatois, L., 2003. (published in 2004)

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Late Cambrian acritarchs from the Santa Rosita Formation: implications for theCambrian-Ordovician boundary in the Eastern Cordillera of northwest Argentina.Revista Brasileira de Paleontologia 5, 47-52.

Rubinstein, C.V., Vaccari, N.E., 2004.Cryptospore assemblages from the Ordovician/Silurian boundary in the Puna,North-West Argentina. Palaeontology, 47 (4), 1037-1061.

Servais, T., Li, J., Stricanne, L., Vecoli, M., Wicander, R., 2004.Acritarchs. In Webby, B. D., Paris, F., Droser, L. D., Percival, I. G. The GreatOrdovician Biodiversification Event. Columbia University Press, New York, p.348-360.

Servais, T., Stricanne, L., Montenari, M., Pross, J., 2004.Population dynamics of galeate acritarchs at the Cambrian-Ordovician transitionin the Algerian Sahara. Palaeontology 47, 395-414.

Servais, T., Wellman, C., 2004.New directions in Palaeozoic palynology. Review of Palaeobotany andPalynology 130 (1-4), 1-14.

Stricanne, L., Munnecke, A., Pross, J., Servais, T., 2004.Acritarch distribution along an inshore-offshore transect in the Gorstian (lowerLudlow) of Gotland, Sweden. Review of Palaeobotany and Palynology 130 (1-4),195-216.

Talbot, M.R., Morley, C.K, Tiercelin, J.J., Le Hérissé A., Potdevin, J.L., LeGall, B., 2004. Hydrocarbon potential of the Meso-Cenozoic TurkanaDepression, northern Kenya. II. Source rocks: quality, maturation, depositionalenvironments and structural control. Marine and Petroleum Geology 21 (1), 63-78.

Vecoli, M. 2004.Stratigraphic and palaeoenvironmental distribution of organic-walled microfossilsin Cambrian-Ordovician transitional strata of borehole Bir Ben Tartar-1 (Tt-1;Ghadamis Basin, southern Tunisia). Memoirs of the Association of AustralasianPalaeontologists 29, 13-30.

Vecoli, M., Le Hérissé, A., 2004.Biostratigraphy, taxonomic diversity, and patterns of morphological evolution ofOrdovician acritarchs (organic-walled microphytoplankton) from the northernGondwana margin in relation to palaeoclimatic and palaeogeographic changes.Earth-Science Reviews 67 (3-4), 267-311.

Vecoli, M., Tongiorgi, M., Quintavalle, M., Massa, D., 2004.Palynological contribution to the Cambro-Ordovician stratigraphy of NWGhadamis Basin (Libya and Tunisia). In: M.J., Salem and K.M., Oun (eds.).Sedimentary Basins of Libya, Second Symposium, Geology of Northwest Libya.Gutenberg Press Ltd, Malta; pp. 110-125.

Wicander, R., 2004.A review of Ordovician Laurentian acritarch assemblages and their relevance topalaeogeographic and biodiversification trends. Memoirs of the Association ofAustralasian Palaeontologists 29, 245-251.

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ABSTRACTS OF CONFERENCE PRESENTATIONS

Given the very numerous conferences held each year worldwide, and the evenmore numerous contributions which are usually submitted to such more or lessformal venues, the following list is certainly much less than complete. I includehere only what some members have submitted in their list of publications for theyear 2004. I think it is necessary to keep abstracts and full papers in separatelists, to avoid confusion; abstracts are often not very useful to refer to (for obviousand well-known reasons which I do not need repeat here) and usually refer toworks in progress: we have a good coverage of that in the “news” section to seewho is doing what. I make an excpetion for the phytopal meeting because it dealsexclusively with acritarchs.Many other abstracts related to acritarch research can be found in the abstractbooks of the XI Palynological Congress, Granada, Spain, 4-9 July 2004(published in: Palinos, Vol. 14); and in the abstract book of the IGCP N° 503meeting: International Symposium on Early Palaeozoic Palaeogeography andPalaeoclimate; Erlangen, Germany; September 1-3 (published in: ErlangerGeologische Abhandlungen, Sonderband 5).

Achab, A., Rubinstein, C.V., Astini, R., 2004.Chitinozoans and acritarchs of the Famatina System, north-west Argentina: anOrdovician perigondwanan volcanic arc. XI International Palynological Congress,Granada, Spain. Polen 14, 143-144.

Albani R., Bagnoli G., Bernardez E., Gutierrez-Marco J. C., Ribecai C., 2004Late Cambrian acritarchs from the « Túnel Ordóvicico del Fabar», CantabrianZone, N Spain. XI International Palynological Congress, Granada, Spain. Polen14, 131.

Bagnoli G., Ribecai C., Albani R., 2004.Changes in some acritarch genera across the Volkhov/Kunda boundary on Öland(Sweden). International. Symposium on Early Palaeozoic Palaeogeography andPaleoclimate, September 1-3, 2004, Erlangen. Erlanger geologischeAbhandlungen Sonderband 5, 20-21.

Dorning, K.J., 2004.Acritarch and chitinozoan evidence of Palaeozoic marine productivity. Abstracts,XI International Palynological Congress, Granada, Spain. Polen 14, 137-138..Abstract available online in the CIMP Newsletter for December 2004:www.shef.ac.uk/~cdimp

Lewandowski, M., Malkowski, K., Moczydlowska, M., Sidorczuk, M.,Abrahamsen, N., 2004.Neoproterozoic paleogeography and environment of the Visingsö basin (southernSweden): evidence from paleomagnetism and stable isotopes. 5th NordicPaleomagnetic Workshop, Helsinki, Finland,Sep.25-Oct.1, 2004, p. 10-15.

Li, J., 2004.Environmental significance of the Ordovician acritarchs from the Tarim Basin,NW China. XI International Palynological Congress, Granada, Spain. Polen 14,133-134.

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Li, J., Kui, Y., 2004.The Ordovician acritarch assemblage from the Meitan Formation, Tongzi, SouthChina: biostratigraphy and biodiversity. Erlanger geologische AbhandlungenSonderband 5, 50-51.

Moczydlowska, M., 2004.Neoproterozoic-Cambrian phytoplankton diversity and response to majorenvironmental perturbations. Abstract Book; 32nd International GeologicalCongress, Florence - Italy, August 20-28, 2004.

Moczydlowska, M., 2004.Neoproterozoic microbiota - adaptations and survival of severe environmentaldisturbances. XI International Palynological Congress, Granada, Spain. Polen 14,p. 129.

Mullins, G. L., Aldridge, R. J., Dorning, K. J., Le Herisse, A, Moczydlowska-Vidal, M., Molyneux, S., Servais, T. Wicander, R., 2004.PhytoPal: a database of Palaeozoic phytoplankton. Abstracts, XI InternationalPalynological Congress, Granada, Spain. Polen 14, 242.Poster at http://www.le.ac.uk/geology/glm2/phytopal/granada.pdfAbstract available online: www.shef.ac.uk/~cdimp

Rubinstein, C. V., Toro, B. A., 2003. (published 2004)Palinomorfos del Llandoveriano medio (Aeroniano superior) de la FormaciónLipeón, Cordillera Oriental, Argentina. Ameghiniana. Resúmenes. Tomo 40. Nº 4.Suplemento: 91-92.

Toro, B.A., Rubinstein, C.V., Waisfeld, B.G., Astini, R.A, 2003. (published2004)Calibración de las asociaciones de palinomorfos y trilobites, con las biozonas degraptolitos del Ordovícico temprano del área de Parcha, Cordillera Oriental,Argentina. Ameghiniana. Resúmenes. Tomo 40. Nº 4. Suplemento: 94-95.

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THESIS ABSTRACT

Lower Palaeozoic acritarchs as proxies for the reconstruction ofpalaeoenvironmentsBy Ludovic Stricanne

Thesis supervised byDr T. Servais (Villeneuve d’Ascq, France)Pr Dr A. Freiwald (Erlangen, Germany)and Dr J. Pross (Tübingen, Germany)

presented on June 28th 2004at Universitaet Tuebingen, Germany

The Lower Palaeozoic is characterised by a major phytoplankton diversification.Organic-walled organisms (acritarchs) played an essential role in primaryproduction. This group is very useful for biostratigraphy, but has also a highpotential for palaeobiogeographical and palaeoecological reconstructions.

Late Cambrian, Ordovician and Late Silurian material was studied in orderto analyse taxonomy, to review published data and to reconstructpalaeoenvironmental conditions and palaeoclimate . This research led to thepublications of six articles attached to the present thesis.

Multivariate statistics on Cambro-Ordovician galeate acritarchs from theAlgerian Sahara allow an alternative classification . The revision of the genusNellia from the same succession is based on the combination of traditionaltaxonomy and statistical approach to demonstrate the high intraspecific variation.

For the evaluation of Ordovician acritarch biodiversity, a complete review ofthe literature has been carried out. The results reflect more regional trends anddo not display global diversity patterns.

The relation between the morphology of the Cambro-Ordovician galeateacritarchs and environmental parameters (such as salinity) is analysed incomparison with modern dinoflagellate cysts. The acritarch distribution acrosscertain facies boundaries has been investigated on a Late Silurian carbonateplatform (Gotland, Sweden). Some acritarch taxa characterise specificpalaeoenvironments. The detailed record of climatic changes in the Late Silurianis reflected by changes in the composition of acritarch assemblages from theGotland succession. The sensitivity of acritarchs to environmental changes mayrepresent an important tool for the reconstruction of the Lower Palaeozoicclimate.

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THESIS ABSTRACT

Lower to Middle Ordovician palynomorphs of the Canning Basin,Western Australia

By Marco QuintavalleSupervisor: Prof. Geoffrey Playford

The University of Queensland, AUSTRALIA

Detailed palynological analysis of 138 core samples from five boreholes drilledthrough Lower to Middle Ordovician sequences of the central northeasternCanning Basin, Western Australia, reveals the presence of moderately diverseand variably preserved palynomorphs (acritarchs, prasinophytes, andchitinozoans), thus providing the material basis for the present account. Thepalynostratigraphic sequence, embracing the Oepikodus communis throughPhragmodus-Plectodina conodont zonal interval, spans (in ascending order) theWillara, Goldwyer, and Nita Formations, of inferred early Arenig to Llanvirn age.

The palynomorph taxa, detailed systematically herein, comprise 67 speciesof acritarchs, seven of prasinophytes, and 21 of chitinozoans. Of these, thefollowing two species of prasinophytes and 14 acritarch species are newlyestablished: Dictyotidium meandricum and Pterospermel la f rancin iae;Aremoricanium hyalinos, A . solaris, Balt isphaeridium tenuicomatum,Buedingiisphaeridium aequalium, B. aspersum, Comasphaeridium setarium,Gorgonisphaeridium crebrum, Micrhistridium pleridium, Polyancistrodoruskunzeanense, Pylantios hadros, Sacculidium? impolitum, Sertulidium amplexum,Stelomorpha calix, and Striatotheca subtilia. Pylantios (typified by P. hadros) andSertulidium (typified by S. amplexum) are defined as new acritarch genera. Threenew combinations are instituted: Baltisphaeridium pugiatum (PLAYFORD &MARTIN), B. variocavatum (PLAYFORD & MARTIN), and Sacculidium furtivum(PLAYFORD & MARTIN); and Ammonidium macilentum PLAYFORD & MARTIN isemended. A large number of palynomorph species are not formally named owingto lack of sufficient or adequately preserved specimens, whereas others arecompared but not positively identified with previously instituted species.

Five, stratigraphically successive acritarch/prasinophyte assemblage zones,ranging in age from early Arenig through early late Llanvirn, are informallyproposed, as follows (ascending order): Athabascaella rossii Assemblage Zone;Loeblichia heterorhabda Assemblage Zone; Sacculidium aduncum AssemblageZone; Aremoricanium solaris Assemblage Zone; and Dactylofusa striatogranulataAssemblage Zone. Four chitinozoan assemblage zones, stratigraphicallycoinciding (within the limits of sampling) with the acritarch/prasinophyte zones,are informally defined as follows (ascending order): Lagenochitina combaziAssemblage Zone (equivalent to the A. rossii and L. heterorhabda AssemblageZones); Conochitina langei Assemblage Zone; Conochitina subcylindricaAssemblage Zone; and Belonechitina micracantha Assemblage Zone.Chronostratigraphic attributions are based principally on associated conodontfaunas. The palynozones facilitate intra-basinal Lower to Middle Ordoviciancorrelations. Whereas the acritarch/prasinophyte zones bear scant similarities tothose established in other parts of the world, the chitinozoan zones showsignificant affiliations with those known from Laurentia.

Palaeogeographically, the Canning Basin chitinozoan assemblagesmanifest clear affinities with coeval suites of low latitude, warm-water Laurentianregions (e.g., northeastern Canada and western Newfoundland). On the other

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hand, the acritarch assemblages exhibit some similarities to those of mid-latitude,temperate-water regions (i.e., South China and Baltica). In general terms,biogeographic inferences based on the Canning Basin’s graptolite and conodontfaunas are in substantial agreement with the palynological evidence presentedhere, showing strong affinities with warm-water (i.e., Laurentia, North China, andTarim) and temperate-water (i.e., South China) regions.