The power of the neglected body: the importance of postcranial anatomy for our understanding of the ecology and evolution of the Rhynchocephalia (Lepidosauria)

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The Rhynchocephalia are one of the two main lineages of the Lepidosauria. They represent the sister taxon to the Squamata (lizards and snakes), one of the most diverse clades of terrestrial vertebrates today. However, in contrast to squamates, rhynchocephalians are today represented by a single species, Sphenodon punctatus, the tuatara of New Zealand. In contrast, during the Mesozoic, rhynchocephalians were both taxonomically and ecologically diverse, and might have surpassed squamates in this respect, at least up to the Jurassic. The fossil record of rhynchocephalians is dominated by jaws and teeth, so that our interpretations of both rhynchocephalian phylogeny and ecology is largely based on characters of the jaws and teeth. However, recent squamates show that the postcranial skeleton can provide important insights into these aspects. In some exceptional fossil lagerstätten, such as the Late Jurassic lithographic limestones of southern Germany, a rich rhynchocephalian fauna is found, with frequently preserved complete or almost complete postcranial remains. This fauna thus represents a unique opportunity to evaluate the importance of postcranial characters for our understanding of rhynchocephalian ecology, diversity and phylogeny. Thus, in this project, we plan to document the morphological diversity of the postcranial skeleton in rhynchocephalians and investigate the importance of postcranial characters for interpreting the ecology and phylogeny within this group. For this, we will use comparisons with modern squamate osteology and myology and apply modern methods of investigation (e.g. CT-scanning) and analysis (e.g. phylogenetic analysis using both parsimony and Bayesian methods). The project is focused on the rhynchocephalian material from the Late Jurassic limestones of southern Germany, but will also take data from postcranial remains of rhynchocephalians from other localities into account.