Tomáš Přikryl

Pelvic and thigh musculature in frogs (Anura) and origin of anuran jumping locomotion

Comparative analysis of the anuran pelvic and thigh musculoskeletal system revealed that the thigh extensors, responsible for the initial phase of jump, the propulsive stroke in swimming and, if used asynchronously, also for walking, are least affected by the transformations observed between anurans and their temnospondyl ancestors (as reflected in contemporary caudates). The iliac shaft and urostyle, two of the most important anuran apomorphies, represent skeletal support for muscles that are mostly protractors of the femur or are important in attaining a crouching position, a necessary prerequisite for rapid escape. All of these muscles originate or insert on the iliac shaft. As the orientation of the pubis, ischium and ilium is the same in anurans, caudates and by inference also in their temnospondyl ancestors, it is probable that the pelvis was shifted from the sacral vertebra posteriorly along the reduced and stiffened tail (urostyle) by the elongation of the illiac shaft. Thus, the original vertical orientation of the ilium was maintained (which is also demonstrated by stable origins of the glutaeus maximus, iliofemoralis and iliofibularis on the tuber superius) and the shaft itself is a new structure. A review of functional analysis of anuran locomotion suggests some clear differences from that in caudates, suggesting that terrestrial jumping may have been a primary locomotor activity, from which other types of anuran locomotion are derived.

Generic diversity and distributional dynamics of the Palaeobatrachidae (Amphibia: Anura)

A small palaeobatrachid from the Late Eocene of Kučlín, Czech Republic is described and compared with Middle Eocene palaeobatrachids from Messel, described here as Palaeobatrachus tobieni (Sanchiz 1998) comb. nov., and with Middle Eocene palaeobatrachids from Geiseltal. P. tobieni is the earliest palaeobatrachid documented by articulated skeletons. The description of the Eocene palaeobatrachids from Messel and Kučlín necessitated a revision of all palaeobatrachid genera. In order to correctly assess taxonomic variation within the Palaeobatrachidae, we studied variation in the frontoparietal, one of the most frequently preserved skeletal elements in the palaeobatrachids, in a sample of Palaeobatrachus grandipes from Bechlejovice, Czech Republic. It was found that other genera in which the frontoparietal is known (Pliobatrachus, Albionbatrachus) basically fit into the range of variation seen in Palaeobatrachus. Therefore, the differences that can be observed (e.g., sculpture in Albionbatrachus) may be interspecific in nature, rather than intergeneric. Moreover, some of the diagnostic characters of these genera are already used to diagnose the palaeobatrachid family (e.g., synsacrum in Pliobatrachus). Accordingly, it is proposed that these genera be synonymized with Palaeobatrachus, and that variations among the currently recognised genera be considered diagnostic at the species level only. The distribution of Eocene palaeobatrachids, encompassing only western and central Europe, contrasts with the distribution of palaeobatrachids in post-Eocene times. This suggests a shift in their distribution between the Late Cretaceous and Palaeocene (western Europe) and the Pliocene and Pleistocene (eastern Europe). The last palaeobatrachids were recorded from the Muchkap interglacial (621–568 Ka) in Russia. This implies that palaeobatrachids, as obligate water-dwellers, did not survive the Oka glaciation (474–425 Ka). They were probably “trapped” between a periglacial zone with temperatures below freezing in the north and a dry steppe zone in the south.

Comparative morphology of the ilium of anurans and urodeles (Lissamphibia) and a re-assessment of the anuran affinities of Nezpercius dodsoni Blob et al., 2001

ABSTRACT Ilia of anurans (frogs) and urodeles (salamanders) are commonly recovered from microvertebrate fossil localities. Ilia in these clades are distinctive when complete and articulated with the rest of the pelvic girdle, but when preserved as isolated and broken fossils they may appear superficially similar. Reliable identification of urodele ilia is further hampered by limited information about the basic structure and contacts of the bone and its variation within the clade. Here we demonstrate that the ilium is more variable among urodeles than previously realized and provide the first detailed inventory of features that are potentially useful for differentiating ilia of anurans and urodeles. Many of these features relate to differences between the two clades in the orientation of the ilium and its contacts with other bones and with soft tissues. Based on the results of our survey, we re-interpret the holotype and two referred ilia of Nezpercius dodsoni (Late Cretaceous; Montana, U.S.A.) as being from an indeterminate urodele, not an anuran as originally described. Additional examples of Late Cretaceous urodele ilia are documented to highlight some of the variation seen in fossil urodele ilia and to aid in the proper identification of such specimens.

Diversity and distribution of fossil codlets (Teleostei, Gadiformes, Bregmacerotidae): review and commentary

The Bregmacerotidae is a family of small-sized, pelagic fish within the Gadiformes (i.e. cods) and their fossils are commonly found in Cenozoic marine sediments as articulated skeletons, isolated otoliths or skeletons with otoliths in situ. Although numerous fossils have been published, and their geographical and chronological distributions are well documented, morphological data are often sparse or confusing. Eighteen fossil species of bregmacerotids have been recognised: 17 species within the middle Eocene–Recent genus Bregmaceros (five species based on articulated skeletons, including two with otoliths in situ, and 12 species based on isolated otoliths alone) and the Miocene Bregmacerina antiqua. Here, we provisionally accept the 12 nominal species based on otoliths. However, we find that only two species of Bregmaceros based on body fossils, and both known by otoliths in situ, are diagnosable: B. albyi (including junior subjective synonym B. bosniaski) from the Miocene–Pliocene of Italy, Austria, Greece, Cyprus, Malta and Algeria, and B. filamentosus (including junior subjective synonym B. prahovanus) from the Eocene–Miocene of Egypt, Iran, Czech Republic, Romania, Georgia, Poland and Russia. For the other two species named for body fossils, we regard Bregmaceros carpathicus as a nomen dubium and exclude it from Bregmacerotidae, and we question whether the monospecific Bregmacerina is a bregmacerotid. We provide descriptions of relevant body fossils (including available type specimens), and summarise and discuss the fossil record for the family.

A new species of the sleeper goby (Gobioidei, Eleotridae) from the České Středohoří Mountains (Czech Republic, Oligocene) and analysis of the validity of the family Pirskeniidae

A new species of gobioid fish Pirskenius Obrhelová, 1961 (P. radoni sp. nov.) is described from Oligocene strata of the České Středohoří Mountains and compared with related species. The new species is characterized by a unique combination of characters that allow it to be separated from P. diatomaceus Obrhelová, 1961. The taxonomic position of the genus Pirskenius is discussed, and its affinity to the family Eleotridae is indicated. The new record documents, together with P. diatomaceus, the oldest known skeletal record of the Eleotridae.KurzfassungEine neue Art der gobioiden Fischgattung Pirskenius Obrhelová, 1961 (P. radoni sp. nov.) wird aus oligozänen Schichten des Böhmischen Mittelgebirges beschrieben und mit verwandten Arten verglichen. Die neue Art ist durch eine einzigartige Kombination von Merkmalen definiert, die sie von P. diatomaceus Obrhelová, 1961 unterscheidet. Die taxonomische Stellung der Gattung Pirskenius wird diskutiert und Affinitäten zu der Familie Eleotridae angenommen. Zusammen mit P. diatomaceus dokumentiert die neue Art die ältesten Skelett-Nachweise der Familie Eleotridae.

Discovery of the oldest Gobius (Teleostei, Gobiiformes) from a marine ecosystem of Early Miocene age

Gobiidae (Gobiiformes, Teleostei) is among the largest families of vertebrates. These fishes are distributed worldwide and contribute significantly to species diversity in marine habitats and reefs. However, their fossil record is sparse prior to the Miocene and little is known about the course of diversification of the clade. Here we report exceptionally well-preserved skeletal remains of the oldest known Gobius from an Early Miocene (Burdigalian) marine ecosystem of Central Europe (Czech Republic). Gobius jarosi Přikryl & Reichenbacher sp. nov. is dated to 19.1–20.4 Ma by biostratigraphical analysis of calcareous nannoplankton from small fragments of the holotype matrix. Gobius jarosi sp. nov. is characterized by a pterygiophore formula of 3-22110 and a premaxilla with a distinctive postmaxillary process, has 11 abdominal and 16–17 caudal vertebrae, six thin spines in the first dorsal fin and one spine and 12 soft rays in the second dorsal fin, one spine and 11 rays in the anal fin, and two anal fin pterygiophores preceding the first haemal spine. Large ctenoid scales cover the body except for its anterior portion and the head. A comparative analysis of meristic and osteological data suggests close affinities between G. jarosi sp. nov. and the extant species G. niger, G. roulei and G. vittatus. Accompanying fish fossils and nannoplankton assemblages indicate that G. jarosi sp. nov., like G. roulei and G. vittatus, lived in an inshore to offshore marine ecosystem. The discovery of such an early member of the lineage leading to the present-day species of Gobius has important implications for the origin and evolution of the Gobiidae, and indicates that diversification of the European Gobiidae began in, but not before, the Early Miocene. http://zoobank.org/urn:lsid:zoobank.org:pub:3229739B-3428-4DFB-9588-4CE875D732D8

Introduction to the special issue “Contributions in honour of Zbyněk Roček”

Over the course of his nearly five decades long career, the Czech herpetologist and palaeontologist Zbyněk Roček (Fig. 1) has become well known for his research on lower vertebrates, especially on the origins, anatomy, functional morphology, development, ecology, systematics and fossil record of frogs. Zbyněk has also been a teacher and supervisor, a generous mentor and a valued colleague for several generations of students and researchers. In recognition of Zbyněk Roček’s many academic contributions and on the twin occasions in 2015 of his being appointed Emeritus Professor at the Czech Academy of Sciences and his 70th birthday, here, we (1) provide a biographical sketch and commentary on his academic contributions and (2) present a collection of papers by some of Zbyněk’s colleagues that echo many of the themes and topics of his research programme. Biographical sketch and commentary on the academic contributions of Zbyněk Roček

Fish fauna of the Camp dels Ninots locality (Pliocene; Caldes de Malavella, province of Girona, Spain) – first results with notes on palaeoecology and taphonomy

The Konservat-Lagerstätte locality Camp dels Ninots (Late Pliocene) in north-eastern Spain was interpreted as a maar lake and its sediments produced, among others, numerous fish fossils. These are represented by articulated (and semi-articulated) specimens and isolated bones and can be classified (within open nomenclature) to two Cyprinidae species: a barb Barbus (‘Luciobarbus’) sp. and a chub Leuciscus sp. The selected specimens of both groups are described and main morphological characters are presented. The composition of the fish fauna clearly indicates a freshwater environment. From the point of the view of taphonomy, it is possible to recognise two different types of preservations of the fish fossils at the locality: (i) larger specimens are preserved in good conditions, with occasional partial dislocations from their natural anatomical position, and relatively quickly buried by sediment, whereas (ii) a second type was observed in smaller specimens with supposed decomposition in the hypoxic environment and with slow burying.

An annotated list of the Oligocene fish fauna from the Osíčko locality (Menilitic Fm.; Moravia, the Czech Republic)

The present article provides an annotated list of the Oligocene fish fauna from the Menilitic Formation of a new Osicko locality (Silesian Unit), collected from two different parts of the formation, i.e., Subchert Member and Dynow Member. The specimens were classified as Keasius sp., Elasmobranchii gen. et spec. indet., Scopeloides glarisianus, Sardinella sardinites, Clupeidae gen. et spec. indet., “Glossanodon” musceli, Anenchelum glarisianum, and Perciformes gen. et spec. indet. The composition of the assemblage suggests mesoto benthopelagic environments. Elasmobranchii; Teleostei; Oligocene; Moravia; Menilitic Formation. Received April 4, 2013 Issued December, 2013

Evidence for fish predation on a coleoid cephalopod from the Lower Jurassic Posidonia Shale of Germany

A specimen of the Early Jurassic actinopterygian fish Pachycormus sp. from the Lower Jurassic Posidonia Shale of Germany has a well preserved filling of the alimentary canal. The region interpreted as the stomach contains numerous hooklets that can be referred to the coleoid cephalopod Phragmoteuthis Mojsisovics, 1882. The presence of arm hooklets clearly demonstrates predation on coleoid cephalopods by actinopterygian fishes.