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[dinosaur] Nothosaurus skull from Kupferzel in Germany + crocodylian intervertebral joint polarity reversion




Ben Creisler
bcreisler@gmail.com

Two recent papers:


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Juliane K. Hinz, Andreas T. Matzke, ÂFelix J. Augustin & Hans-Ulrich Pfretzschner (2020)
A Nothosaurus (Sauropterygia) skull from Kupferzell (Triassic, late Ladinian; SW Germany)
Neues Jahrbuch fÃr Geologie und PalÃontologie - Abhandlungen 297(1): 101 - 111
DOI: 10.1127/njgpa/2020/0915
https://www.schweizerbart.de/papers/njgpa/detail/297/93995/A_Nothosaurus_Sauropterygia_skull_from_Kupferzell_Triassic_late_Ladinian_SW_Germany


Although the Triassic fossil Lagerstaette Kupferzell (Lettenkeuper, Erfurt Formation) is well known for the abundance of well-preserved vertebrate fossils, sauropterygian remains are still unpublished. Here, we describe an only partially preserved Nothosaurus skull from Kupferzell and refer it to Nothosaurus giganteus. The skull described herein is theâsecond occurrence of N. giganteus from the Lower Keuper of the Germanic Basin and the first skull aside from the material from the Hoheneck Kalk which was originally referred to N. chelydrops and is now treated as a junior synonym of N. giganteus. The presence of such large predatory marine reptiles indicates a stronger marine influence in the Lettenkeuper than currently thought.

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Masaya Iijima Â& Tai Kubo (2020)
Intervertebral joint polarity reversions in extant and extinct crocodylians
Acta Zoologica (advance online publication)
doi: https://doi.org/10.1111/azo.12346
https://onlinelibrary.wiley.com/doi/10.1111/azo.12346


Procoely in presacral and caudal vertebrae except the biconvex first caudal vertebra is regarded as a key diagnostic feature of eusuchian crocodylomorphs, although its individual variation, which may have an impact on the evolutionary and functional interpretations, remains unexplored. Here, we examined 19 extant species as well as a few fossil species of crocodylians to identify individual (intraspecific) variation in the intervertebral joint polarities. We found joint alteration in eight individuals from seven extant species and three individuals from two extinct species. Most variant specimens show sacrocaudal joint alteration, while single Osteolaemus tetraspis peculiarly displays multiple joint polarity reversions (cotyle to condyle and vice versa) in anterior caudal vertebrae. Because the sacrocaudal joint polarity is frequently reversed and the first caudal vertebra becomes procoelous, caution should be taken when identifying an isolated first caudal vertebra of basal and outgroups of eusuchians. Almost exclusive occurrences of joint alteration at the less mobile sacrocaudal joint in crocodylians are consistent with the hypothesis that the joint alteration takes place at joints with a lesser range of motion.

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