A new Trimerocephalus species (Trilobita, Phacopidae) from ... · In honour of Fryderyk Franciszek Chopin, the most famous Polish composer during the Romantic period of classical

TERMS OF USEThis pdf is provided by Magnolia Press for private/research use. Commercial sale or deposition in a public library or website is prohibited.

ZOOTAXAISSN 1175-5326 (print edition)

ISSN 1175-5334 (online edition)Copyright © 2013 Magnolia Press

Zootaxa 3626 (3): 345–355 www.mapress.com/zootaxa/ Article

http://dx.doi.org/10.11646/zootaxa.3626.3.3http://zoobank.org/urn:lsid:zoobank.org:pub:61A4F4E5-3F5A-4BA6-8535-DBF2A7E62226

A new Trimerocephalus species (Trilobita, Phacopidae) from the Late Devonian (Early Famennian) of Poland

ADRIAN KIN1,2,4 & BŁAŻEJ BŁAŻEJOWSKI2,3

1Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Cracow, Poland2”Phacops” – Association of Friends of Geosciences, Targowa 29, Łódź 90-043, Poland. E-mail: [email protected]

3Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, 00-818 Warsaw, Poland4Deceased

Abstract

This study presents a detailed morphological analysis of a new species belonging to the blind trilobite Trimerocephalus McCoy, 1849, T. chopini n. sp., based on exceptionally well preserved articulated specimens from the Late Devonian (Early Famennian) of the Holy Cross Mountains in central Poland. The occurrence of this taxon in Kowala Quarry near Kielce has been reported previously, with specimens often found in single-file queues representing migratory behaviour that was followed by a mass mortality event that preserved these assemblages. The new taxon is compared with other species of Trimerocephalus and is interpreted as being most closely related to a clade consisting of T. caecus, T. lelievrei, T. mimbi, T. shotoriensis and T. tardispinosus.

Key words: Phacopinae, Late Devonian, Famennian, Holy Cross Mountains, Poland

Introduction

The blind phacopine genus Trimerocephalus McCoy, 1849 appears to have almost worldwide distribution in Late Devonian (Famennian) strata, except for America. Seventeen species of this genus are known (Crônier, 2003; Feist et al., 2009), six of which occur in Poland: T. caecus (Gürich, 1896), T. dianopsoides Osmólska, 1963, T. interruptus Berkowski, 1991, T. mastophthalmus (Richter, 1856), T. polonicus Osmólska, 1958, and T. (Trifoliops) trifolius (Osmólska, 1958). These species are widely distributed in the Fammenian carbonate strata of the Holy Cross Mountains (Osmólska, 1958, 1963; Radwański et al., 2009), while a single species is also found at Dzikowiec (formerly Ebersdorf) in Silesia (Lewowicki, 1959).

Numerous specimens of Trimerocephalus were recently collected from yellowish marly shales of Early Famennian age that are exposed in the western part of the northern wall in Kowala Quarry (near Kielce in the Holy Cross Mountains, south-central Poland; Fig. 1). This occurrence was previously reported by Kin and Radwański (2008) and Radwański et al. (2009), but without detailed taxonomic and morphological analysis. The total thickness of the Famennian succession exposed in this quarry, which consists of five units (i.e., H–L = Palmatolepis triangularis to Palmatolepis expansa conodont zones), is approximately 180 m (see Berkowski, 2002). Age-diagnostic conodonts from the marly sediments—that also contain both monospecific trilobite queues and rare single specimens—are indicative of the lower part of the Palmatolepis marginifera Zone (see Radwański et al., 2009, p. 460; Unit I of Berkowski, 2002).

The vast majority of Trimerocephalus specimens forming queues are partially or fully articulated and show considerable size variation (i.e., 5–20 mm in length). These trilobites are positioned on the tops of bedding surfaces, forming a single queue composed of a few to several specimens. The queue length is limited simply by the size of the joint-cracked stratum surface. The occurrence of the queues is restricted to two main horizons of marly shales, and a few queues were also found on the surface of some calcareous concretions, which occur irregularly within those horizons (Radwański et al., 2009). Successive horizons also contain isolated juvenile (Fig.

Accepted by J. Paterson: 30 Jan. 2013; published: 14 Mar. 2013 345


3A, C), sub-adult (Figs 2, 3B, D–F) and adult specimens (Fig. 4) that show identical morphologies with the sub-adult individuals represented in the queue assemblages (see Radwański et al., 2009).

Specimens of Trimerocephalus from Kowala Quarry from were tentatively assigned to T. mastophthalmus by Radwański et al. (2009). Here we provide a much more detailed investigation of the morphology of this taxon and identify it as a new species, T. chopini n. sp.

FIGURE 1. A: Map of Poland with the location of the Holy Cross Mountains region (grey rectangle). B: Generalised geologic map of the Holy Cross Mountains region and the location of Kowala Quarry (black arrow). C: Map of Kowala Quarry with the location of the studied section exposed in the western part of the northern quarry wall indicated by the black arrow.

Material and methods

The studied specimens (i.e., those preserved in queues and also single individuals, including the holotype) were collected by one of us (AK) in Kowala Quarry between 1995 and 2010. Most specimens are preserved as complete or nearly complete exoskeletons, representing both meraspid (Figs 2, 3) and holaspid stages (Fig. 4). Most show a variable degree of deformation. The collected material are housed at the Institute of Paleobiology, Polish Academy of Science in Warsaw (ZPAL Tr.8; old no. MGFA/Kow/TA). A total of around 450 specimens were studied and prepared manually at the Museum of Association of Friends of Geosciences, Łódź, including 78 trilobite queues. 347 individuals were subject to detailed measurements using vernier calipers with an accuracy of 0.01 mm and, in

KIN & BŁAŻEJOWSKI346 · Zootaxa 3626 (3) © 2013 Magnolia Press


part, using an advanced measurement technique associated with X-ray microcomputed tomography of the marls containing the trilobite queues. Scanning electron micrographs (e.g., Figs 2, 3, 4A–C) were taken using a Philips XL20 SEM at the Institute of Paleobiology, Polish Academy of Sciences (Warsaw, Poland). Specimens coated with ammonium chloride were photographed using a Canon EOS 400D digital camera (e.g., Fig. 4D, E). Morphological terminology follows Whittington et al. (1997), Crônier (2003) and Crônier et al. (2011). Ontogenetic nomenclature follows that of Crônier et al. (1998).

Systematics

Family Phacopidae Hawle & Corda, 1847

Trimerocephalus McCoy, 1849

Type species. Phacops mastophthalmus Richter, 1856.

Trimerocephalus chopini n. sp.Figures 2–4

Material. Holotype, Tr.8/12.02.79, near complete exoskeleton (pygidium absent) of a late meraspid (M10) (Fig. 3F), from Unit I (late Early Famennian, Palmatolepis marginifera Zone) in Kowala Quarry, 7 km southwest of Kielce, Holy Cross Mountains, central Poland, 50° 47' 46.21" N 20° 33' 57.52" E.

Etymology. In honour of Fryderyk Franciszek Chopin, the most famous Polish composer during the Romantic period of classical music, also called the ‘poet of the piano’.

Diagnosis. Facial suture running along marginal furrow and not cutting cheek; the latter showing a very slight recess in contact with suture. Border furrows generally indistinct, but very shallow and wide near truncated genal angle. Ocular protuberance absent. Preoccipital furrow continuous along its length. Preoccipital ring straight, with two small, median tubercles. Occipital ring without median node. Pygidium trapezoidal with posterior margin almost rectilinear, width to length ratio of 2.8:1. Glabella and cheeks covered by very large to massive granules, usually uniform in size. Carapace covered by fine and moderately dense granulation.

Description. Cephalon semicircular in outline, length to width ratio about 0.5. Glabella subpentagonal in outline, wide, rounded anteriorly with antero-lateral angles truncated (Figs 3F and 4A–C), length to width ratio about 0.6. Glabellar furrows S2 and S3 usually poorly developed, only visible on partially exposed internal moulds of glabellar area on three individuals [specimens: Kow / TA 76 (Radwański et al., 2009, pl. 2, fig. 3b) and Kow / TA 89, 90]; S2 short, bent obliquely upward and positioned very close to preoccipital furrow; posterior ramus of S3 very short and bent obliquely downward (as in T. caecus). Preoccipital furrow straight, well developed and of equal depth. Preoccipital ring straight, slightly convex with two small median tubercles. Occipital furrow slightly bent medially. Occipital ring wide, convex and without median node. Facial suture runs within the antero-lateral border furrow and does not extend onto the cheeks; cheeks exhibit a small recess in contact with suture (e.g., Figs 3F, 4A–C). In dorsal view, the margins of the glabella and cheeks are highly vaulted; cheek areas triangular in outline, with rounded to truncated posterolateral genal angles. Axial furrows deep and moderately wide, diverging forwards at an angle of about 55°. Lateral and posterior borders are widest at posterolateral corner of cephalon. Vincular furrow in holaspid moderately deep, straight medially, strongly directed transversely with smooth edges (Fig. 4D–E). In the genal part it is directed posteriorly (parallel to the cheek), and is very slightly crenulated with small, shallow pits (Fig. 4E).

Thorax of 11 segments. Axial rings straight (tr.). Pleurae with flat fulcrum (bent backward) that is covered in fine granules. Pleural furrows wide and distinct, subdividing two convex bands. The anterior band is narrower (Fig. 2A–B).

Pygidium almost three times as wide as long. Axial furrows moderately deep. Pygidial axis long and wide (Fig. 2C). Ring furrows (5 + 1) straight, with anteriormost furrows more distinct than weakly developed posterior furrows. Articulating half ring as wide as first axial ring. Interpleural and pleural furrows (4) rather indistinct, except first two pleural furrows (Fig. 2C).

Zootaxa 3626 (3) © 2013 Magnolia Press · 347NEW SPECIES OF TRIMEROCEPHALUS


FIGURE 2. Partially complete meraspis (degree M10; librigenae absent) of Trimerocephalus chopini n. sp. from Early Famennian marly shales at Kowala Quarry, Holy Cross Mountains, central Poland. A and B: Dorsal and oblique lateral views, respectively. C: Enlargement of pygidium.



FIGURE 3. Meraspides (degrees M8-M10) of Trimerocephalus chopini n. sp. from Early Famennian marly shales at Kowala Quarry, Holy Cross Mountains, central Poland. A: Incomplete, exfoliated, dorso-laterally deformed meraspis M8 in dorsal view (pygidium is absent). B: Almost complete meraspis M9 in dorsal view (pygidium is not intact). C: Complete, slightly deformed meraspis M8 with partially visible pygidium, in dorsal view. D and E: Nearly complete, slightly deformed meraspis M10 (librigenae absent) in oblique posterior and dorsal views, respectively. F: Incomplete and dorsally deformed meraspis M10 (holotype; ZPAL Tr.8/12.02.79) in dorsal view (pygidium absent).



FIGURE 4. Almost complete internal mould of a holaspid(?) cephalon of Trimerocephalus chopini n. sp. from Early Famennian marly shales at Kowala Quarry, Holy Cross Mountains, central Poland. A–C: Dorsal, anterior and lateral views, respectively. D: Oblique ventral view showing vincular furrow. E: Details of weakly crenulated genal part of vincular furrow, with white arrows indicating shallow pits.

Morphological variation. Amongst studied representatives of Trimerocephalus chopini, the following morphological variations have been observed:

1) In most cephala examined, the genal angle is truncated, but in some it is rounded. Specimens that exhibit the latter condition are typically flattened, thus may represent taphonomic (as opposed to true morphological) variants.

2) Most studied specimens do not show clear lateral glabellar furrows S2 and S3, which are visible only on internal moulds of three specimens. However, in other internal moulds these furrows are completely absent. Similar variation in the development of the glabellar furrows has been documented in Trimerocephalus dianopsoidesfrom the Holy Cross Mountains (Osmólska 1963).

3) Cephalic tuberculation varies throughout ontogenesis. Relatively small granules occur in earlier meraspides (e.g., Fig. 3B, C) and become gradually larger on cephala assigned to subsequent meraspides (i.e., sub-adult representatives, e.g., Figs 2A, B, 3E, F). Slight differences in cephalic tuberculation (i.e., dimension of granules) also occur between individuals representing the same ontogenetic stages (compare specimens in Fig. 3E, F). The cephalic ornamentation in T. chopini closely resembles that of Trimerocephalus shotoriensis Feist in Feist, Yazdi and Becker, 2003 (see Table 1).



TABLE 1. Comparison of nine morphological features between Trimerocephalus chopini n. sp. and selected representatives of the genus Trimerocephalus. Feature 1: facial sutures that do not cut the cheeks; Feature 2: a well developed, straight preoccipital furrow, S1; Feature 3: absence of ocular protuberances; Feature 4: coarse cephalic tuberculation; Feature 5: a trapezoidal pygidium; Feature 6: preoccipital ring (L1) with two median tubercles; Feature 7: the absence of an occipital median node; Feature 8: cheeks form very slight recess in contact with facial suture; Feature 9: truncated genal angle. Plus symbol (+) denotes the above-mentioned conditions are present.

Comparison of Trimerocephalus chopini to other species. For the purposes of this comparison, we follow Crônier’s (2003) phylogenetic groupings for the better known representatives of Trimerocephalus. Accordingly, on the basis of 23 morphological characters, three clades were distinguished among early Famennian representatives of this genus: T. caecus, T. lelievrei, T. shotoriensis and T. tardispinosus [clade 1]; T. procurvus, T. interruptus, T. sponsor and T. polonicus [clade 2]; and T. dianopsoides, T. (Trifoliops) nigritus, T. (Trifoliops) trifolius, T.? steinachensis and T. mastophthalmus [clade 3] (cf. Crônier, 2003, fig. 8).

Key morphological features of Trimerocephalus chopini that have phylogenetic significance include (Table 1): (1) facial sutures that do not cut the cheeks; (2) a well developed, straight preoccipital furrow, S1; (3) a lack of ocular protuberances; (4) coarse cephalic tuberculation; (5) a trapezoidal pygidium; (6) a preoccipital ring with two median tubercles; (7) the absence of an occipital median node; (8) a slight recess in the cheeks in association with the facial suture; and (9) a truncated genal angle. These features suggest a close relationship to members of clade 1 (mentioned above), in addition to the recently erected T. mimbi from the Early Famennian (do II = rhomboideaZone) of Australia (Feist et al., 2009) (see Table 1).

The following list outlines the main morphological differences of Early Famennian species of Trimerocephalusfrom Poland (mentioned above), Iran (T. shotoriensis; Feist et al., 2003) and Australia (T. mimbi; Feist et al., 2009), and the new species (T. chopini):

- Trimerocephalus caecus differs in its anteriorly curved preoccipital furrow (S1), rounded genal angle, and the presence of an occipital median node (Table 1);

- Trimerocephalus dianopsoides differs in the presence of ocular protuberances and the poor segmentation of the pygidium (Table 1);

- Trimerocephalus interruptus differs in the outline of the facial suture that cuts the cheek, the fine and condensed granulation, and poorly segmented lenticular pygidium;

- Trimerocephalus mastophthalmus differs in the outline of the facial suture that cuts the cheek, the presence of ocular protuberances, and much finer granulation of the cephalon (Table 1);

- Trimerocephalus mimbi differs in having a medially ill-defined preoccipital furrow (S1), rounded genal angle, a deep lateral border furrow and much deeper vincular furrow (Table 1);

- Trimerocephalus polonicus is represented only by cephala of early instars, but differences include a sub-semicircular outline (but strongly pointed anteriorly), a facial suture that cuts the cheeks, and very sparse tuberculation;

- Trimerocephalus (Trifoliops) trifolius differs in the trilobed outline of the cephalon, a facial suture that cuts the cheeks, and the presence of ocular protuberances;

- Trimerocephalus shotoriensis differs in exhibiting a rounded genal angle and a subtrapezoidal outline of the pygidium (Table 1).

Taxa Feature 1 Feature 2 Feature 3 Feature 4 Feature 5 Feature 6 Feature 7 Feature 8 Feature 9

T. chopini + + + + + + + + +

T. caecus + - + - - + - - -

T. lelievrei + - + - - + - - -

T. dianopsoides + - - - + - - - -

T. mastophtalmus - - - - - - + - -

T. mimbi + - + - - + + - -

T. shotoriensis + + + + - + - - -



Crônier (2003) emphasised the acquisition of a marginal facial suture that does not cut the cheeks and the presence of an occipital median node as important morphological features in tracing the evolutionary trends in Trimerocephalus, despite being homoplastic. Trimerocephalus chopini conforms to most character acquisitions in the T. caecus plexus, but lacks the occipital median node, and appears to be most closely related to T. shotoriensis(see Table 1 for comparison). Interestingly, specimens of T. caecus described by Osmólska (1958) from the Holy Cross Mountains also lack an occipital median node (as in T. chopini), but do show all the other characteristic features for this widely distributed species (for details, see Crônier, 2003). It also should be clearly emphasized here that all representatives of T. caecus known from outside of Poland possess the occipital median node (Osmólska, 1958; Crônier, 2003). It is therefore possible that specimens of T. caecus from Poland represent the most ancestral populations (lacking the occipital median node) or, more probably, specific ecophenotypic variants of that species. Consequently, the absence of the occipital median node in T. chopini may be due to atavism. The only other species that seems to lack the occipital median node is T. mimbi (see Table 1), but this taxon is known only from the holotype cephalon (specimen WAM. 07.284; Feist et al., 2009, p. 23), hence additional specimens are needed to confirm if this is a true absence in this species.

Discussion

A detailed re-examination of all collected material assigned to T. chopini n. sp. allowed verification of the number of thoracic segments amongst specimens that form queues (Radwański et al., 2009) and single individuals. The new material represents a few ontogenetic degrees, most of which belong to the meraspid period, although two holaspides are also present (see Fig. 4). Radwański et al. (2009, p. 461) suggested that the maximum number of segments among specimens forming queues is 11, but this was rarely observed, with most individuals typically showing nine or 10 segments. Our investigation showed that all individuals forming queues have either nine or 10 thoracic segments, as is the case for most individual specimens of T. chopini (Figs 2, 3B, D–F). Our re-examination of specimens in queues also included those that are not fully visible, including those obscured by other individuals. This was made possible by imaging the marl slabs using X-ray microcomputed tomography (XMT). This imaging technique also revealed preserved soft parts, e.g., walking appendages and antennae, which will form the basis of a future study.

FIGURE 5. Graphical representation of the seven distinct size categories within meraspid degrees M9 and M10 of Trimerocephalus chopini n. sp., based on measurements of hundreds of queue specimens from Kowala Quarry (see Radwański et al., 2009). Meraspides are shown in dorsal view.



The only holaspides of T. chopini are represented by a partially preserved, enrolled specimen (i.e., internal mould without pygidium; details of the cephalon are shown in Fig. 4A–E), and a strongly deformed moult specimen (not illustrated) that has 11 thoracic segments and preserved in “Salterian mode” (sensu Richter, 1937 = phacopine mode of moulting, see Osmólska, 1963; Speyer, 1985). Both holaspides were found about 20 cm above the second queue horizon.

Individuals of Trimerocephalus chopini preserved in the queues exhibit considerable size variation within a single meraspid degree (Radwański et al., 2009) (Figs 5, 6). However, detailed investigations of those specimens showed no other significant morphological differences. Only minor morphological changes are evident between degrees M9 and M10: a coarsening of cephalic ornamentation, a slight widening of thoracic pleurae, and changes in the shape of the cephalon; a similar ontogenesis between M9 and M10 has been observed in other representatives of Trimerocephalus, i.e., T. dianopsoides (Osmólska, 1963) and T. lelievrei (Crônier et al., 1998). Measurements on hundreds of queue specimens reveal seven distinct size categories amongst meraspides: three among representatives of degree M9 and four among representatives of degree M10 (Fig. 5; see also Radwański et al., 2009), with intermediate sizes being extremely rare. The smallest M9 and M10 individuals are 5 and 9 mm in exoskeletal length, respectively, and the largest M9 and M10 specimens are 12 and 20 mm in exoskeletal length, respectively; average lengths of M9 and M10 are 9 and 14 mm, respectively (Figs 5, 6).

FIGURE 6. Bivariate plot of cephalic length (mm) versus width (mm) in meraspid degrees M9 and M10 of Trimerocephalus chopini n. sp. Presented data include only complete, undeformed specimens from the queues (see Radwański et al., 2009).

The observed size variation within a single meraspid degree has been verified amongst individuals of Trimerocephalus chopini contained within queues from both marl horizons. The presence of successive size categories within a single population (i.e., all individuals forming the queues from a single marl horizon) seems to



exclude the possibility of sexual dimorphism amongst individuals, although size variation amongst members of each sex in a single cohort is relatively common in modern arthropods (Stillwell et al., 2010). The rare occurrence of intermediate forms between the size categories of each meraspid degree seems to also exclude possible polymorphism. Distinct size categories within a single instar have been identified among some modern marine arthropods and are considered to be the result of phenotypic plasticity (e.g., Marinowic and Mangel, 1999; Wilmer et al., 2000; Pigliucci, 2001; but see Stillwell and Davidowitz, 2010). In the case of T. chopini, it is possible that the size categories within each meraspid degree represent multiple moult cycles, i.e., true instars (Hughes et al., 2006). If this is correct, T. chopini would have undergone at least three moulting episodes during degree M9 before releasing a single segment into the thorax (to produce M10), and subsequently a further four moult cycles during degree M10.

Acknowledgements

We would like to sincerely thank Katarzyna Kin for help with the field investigation. We are grateful to Peter Walsh (University of Silesia), Carlton E. Brett (University of Cincinnati) and Wojtek Majewski (Institute of Paleobiology PAS) for constructive advice on improving the manuscript. We express our thanks to: Andrzej Radwański (Warsaw University) for valuable discussion; Andrzej Baliński (Institute of Paleobiology PAS) for assistance with photography; and Agata Woźniakowska (Łódź) and Ola Hołda-Michalska (Institute of Paleobiology PAS) for assistance with constructing figures. The constructive reviews by C. Crônier (University of Lille) and R. Feist (University of Mont-pellier) greatly improved the paper. Last but not least, we wish to acknowledge all the members of the ‘Phacops’ Association for helpful advice during the early phase of this investigation. This paper is dedicated to the memory of late Professor Michał Gruszczyński (1952–2011).

References

Berkowski, B. (1991) A blind phacopid trilobite from the Famennian of the Holy Cross Mountains. Acta Palaeontologica Polonica, 36, 255–264. http://dx.doi.org/10.4202/app.2007.0066

Berkowski, B. (2002) Famennian Rugosa and Heterocorallia from southern Poland. Palaeontologia Polonica, 61, 3–88. Crônier, C. (2003) Systematic relationships of the blind phacopine trilobite Trimerocephalus, with a new species from

Causseset-Veyran, Montagne Noire. Acta Palaeontologica Polonica, 48, 55–70.Crônier, C., Bignon, A. & François, A. (2011) Morphological and ontogenetic criteria for defining a trilobite species: the

example of Siluro-Devonian Phacopidae. Comptes Rendus Palevol, 10, 143–153. http://dx.doi.org/10.1016/j.crpv.2010.10.003

Crônier, C., Renaud, S., Feist, R. & Auffray, J.C. (1998) Ontogeny of Trimerocephalus lelievrei (Trilobita, Phacopida), a representative of the Late Devonian phacopine paedomorphocline: a morphometric approach. Paleobiology, 24, 359–370.

Feist, R., Yazdi, M. & Becker, T. (2003) Famennian trilobites from the Shotori Range, E-Iran. Annales de la Société Géologique du Nord, Lille: 10, 2ème série, 285–295.

Feist, R., McNamara, K.J., Crônier, C. & Lerosey-Aubril, R. (2009) Patterns of extinction and recovery of phacopid trilobites during the Frasnian-Famennian (Late Devonian) mass extinction event, Canning Basin, Western Australia. Geological Magazine, 146, 12–33. http://dx.doi.org/10.1017/S0016756808005335

Gürich, G. (1896) Das Palaeozoicum im Polnischen Mittelgebirge. Verhandlungen der Russisch−Kaiserlichen Mineralogischen Gesellschaft, 32, 1–539.

Hawle, I. & Corda, A.J.C. (1847) Prodom eine Monographie der böhmischen Trilobiten. Abhandlungen der königlischen böhemischen Gesellschaft der Wissenschaften, 5, 1–176.

Hughes, N.C., Minelli, A. & Fusco, G. (2006) The ontogeny of trilobite segmentation: a comparative approach. Paleobiology, 32, 602–627. http://dx.doi.org/10.1666/06017.1

Kin, A. & Radwański, A. (2008) Trimerocephalus life-position files from the Famennian of Kowala Quarry (Holy Cross Mountains, Central Poland). Polish Academy of Sciences, Institute of Paleobiology, 9th Paleontological Conference, Warszawa, 10–11 October 2008; Abstracts, p. 44.

Lewowicki, S. (1959) Fauna wapieni klimeniowych z Dzikowca Kłodzkiego. Biuletyn Instytutu Geologicznego, 146, 73–113.Marinovic, B. & Mangel, M. (1999) Krill can shrink as an ecological adaptation to temporarily unfavourable environments.

Ecology Letters, 2, 338–343.


http://dx.doi.org/10.1016/j.crpv.2010.10.003

http://dx.doi.org/10.1016/j.crpv.2010.10.003


McCoy, F. (1849) On the classification of some British fossil Crustacea with notices of new forms in the university collection at Cambridge. Annals and Magazine of Natural History, 2, 392–414. http://dx.doi.org/10.1080/03745486009494858

Osmólska, H. (1958) Famennian Phacopidae from Holy Cross Mts (Poland). Acta Palaeontologica Polonica, 3, 119–148. http://dx.doi.org/10.4202/app.2007.0066

Osmólska, H. (1963) On some Famennian Phacopinae (Trilobita) from the Holy Cross Mountains (Poland). Acta Palaeontologica Polonica, 8, 495–523. http://dx.doi.org/10.4202/app.2007.0066

Pigliucci, M. (2001) Phenotypic Plasticity: Beyond Nature and Nurture. Johns Hopkins University Press, Baltimore, MD, pp. 1–328. http://dx.doi.org/10.2979/VIC.2001.43.2.328

Radwański, A., Kin, A. & Radwańska, U. (2009) Queues of blind phacopid trilobites Trimerocephalus: A case of frozen behaviour of Early Famennian age from the Holy Cross Mountains, Central Poland. Acta Geologica Polonica, 59, 459–481.

Richter, R. (1937) Von Bau und Leben der Trilobiten. 8. Die Salter’sche Einbettung als Folge und Kennzeichen des Häutungs-Vorgangs, Senckenbergiana, 19, 413–431.

Richter, R. (1856) Beitrag zur Paläontologie des Thüringer Waldes. Erster Theil. Denkschriften der kaiserlichen Akademie der Wissenschaften, mathematisch – naturwissenschaftlichen, 11, 87–138.

Speyer, S.E. (1985) Moulting in phacopid trilobites. Transactions of the Royal Society of Edinburgh, 76, 239–259. http://dx.doi.org/10.1017/S0263593300010476

Stillwell, R.C. & Davidowitz, G. (2010) Sex differences in phenotypic plasticity of a mechanism that controls body size: Implications for sexual size dimorphism. Proceedings of the Royal Society of London, B, 277, 3819–3826. http://dx.doi.org/10.1098/rspb.2010.0895

Stillwell, R.C., Blanckenhorn, W.U., Teder, T., Davidowitz, G. & Fox, C.W. (2010) Sex differences in phenotypic plasticity affected variation in sexual size dimorphism in insects: from physiology to evolution. Annual Review of Entomology, 55, 227–245. http://dx.doi.org/10.1146/annurev-ento-112408-085500

Whittington, H.B., Chatterton, B.D.E., Speyer, S.E., Fortey, R.A., Owens, R.M., Chang, W.T., Dean, W.T., Fortey, R.A., Jell, P.A., Laurie, J.R., Palmer, A.R., Repina, L.N., Rushton, A.W.A., Shergold, J.H., Clarkson, E.N.K.,Wilmot, N.V. & Kelly, S.R.A. (1997) Treatise on Invertebrate Paleontology, Part O, Arthropoda 1, Trilobita. Revised. 560 pp. The Geological Society of America and University of Kansas Press, Lawrence.

Wilmer, P., Stone, G. & Johnston, I. (2000) Environmental Physiology of Animals. Blackwell Science, Oxford, pp. 1–754.


http://dx.doi.org/10.4202/app.2007.0066

http://dx.doi.org/10.4202/app.2007.0066

http://dx.doi.org/10.1017/S0263593300010476

http://dx.doi.org/10.1017/S0263593300010476

http://dx.doi.org/10.1098/rspb.2010.0895

http://dx.doi.org/10.1098/rspb.2010.0895

Documents

A new Trimerocephalus species (Trilobita, Phacopidae) from ... · In honour of Fryderyk Franciszek Chopin, the most famous Polish composer during the Romantic period of classical