Fossil Frogs of the Genus Palaeobatrachus (Amphibia: Anura)

About this book

Palaeobatrachidae are an extinct family of frogs whose earliest members are recorded from the Middle Eocene (Geiseltal, Messel, Germany), almost 50 million years ago, although there are indications that they appeared as early as before the Cretaceous mass extinction event and survived almost to our times. Their last survivors are recorded from the Middle Pleistocene, less than 0.5 million years ago, such that they were contemporaries of Neanderthal man. Their last fossil evidence is from the regions that were adjacent to the Pleistocene continental glacier. Like today's pipid frogs (e.g. Xenopus), they were obligate water dwellers, not able to make long excursions onto dry land. Without exaggerating, they literally died out frozen in their ponds.

Permanent life in water has a uniforming effect. This is why they all looked similar to one another, which is a source of difficulty for taxonomists. On the other hand, one cannot overlook features they have in common with pipids, restricted to the southern hemisphere. Palaeobatrachus and Xenopus are undoubtedly related, but when and why ancestors of Palaeobatrachus immigrated to the western part of northern Eurasia but not to its eastern part and not to North America remains a puzzling question. Thus, being acquainted with Palaeobatrachus means to be invited on an excursion not only into comparative anatomy, but also into palaeogeography and many other fields of palaeontology.

Last but not least, Palaeobatrachus was the first fossil frog scientifically described, as early as in 1831. Since that time, many excavation sites from which original material came have ceased to exist; thus there is no possibility that further material will be recovered. What is now deposited in scientific collections is the unique and limited source of data for future comparative studies. This is one of the main reasons why this rich illustrated review was published.

Contents

Introduction 2
Material and Methods 3
      Localities 3
      Material 3
      Character modules 5
      Determination of the relative individual age 7
      Morphometric analysis 7
Results 8
      Development of the frontoparietal during metamorphosis 8
      Frontoparietal in postmetamorphic development 9
      Notes on frontoparietal structure and its variation in adults 10
      Variation of frontoparietals in adults from Bechlejovice 10
      Interspecific variation of frontoparietals 10
      Development of the transverse processes (including ribs) 11
      Development of the synsacrum 12
      Variations of the synsacrum in adults 12
      Clustering character modules 13
      Morphometric evaluation 17
      Systematic palaeontology 17
            Palaeobatrachus Tschudi, 1838 17
            Palaeobatrachus tobieni (Wuttke in Sanchiz, 1998) 19
            Palaeobatrachus sp. 20
            Palaeobatrachus gracilis Meyer, 1857 21
            Palaeobatrachus novotnyi Špinar, 1972 22
            Palaeobatrachus minutus sp. nov. 23
            Palaeobatrachus bohemicus Meyer, 1860 24
            Palaeobatrachus laubei Bieber, 1881 26
            Palaeobatrachus luedeckei Wolterstorff, 1886 28
            Palaeobatrachus diluvianus (Goldfuss, 1831a) 29
            Palaeobatrachus grandipes (Giebel, 1851) 30
            Palaeobatrachus gigas Meyer, 1852 31
            Palaeobatrachus sp. 33
            Palaeobatrachus robustus Hossini & Rage, 2000 34
            Palaeobatrachus hauffianus (Fraas, 1909) 36
            Palaeobatrachus hiri Venczel, 2004 37
            Palaeobatrachus codreavladi sp. nov. 39
            Palaeobatrachus eurydices Villa, Rocek, Tschopp, van den Hoek Ostende & Delfino, 2016 40
            Palaeobatrachus langhae (Fejervary, 1917) 42
Discussion 45
      Species diversity and anatomical evolution 45
      Unresolved taxonomic problems 48
      Palaeogeographic context 50
      Taxa removed from the list of valid species of Palaeobatrachus 52

Acknowledgements 53
References 53
Table 1 58
Plates 1–35 63
Appendices 142

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