New reptiles from the Middle Triassic of Germany and the early evolutionary history of lepidosaurs
Final Report Abstract
The numerous new finds of reptiles from the Vellberg locality (Baden-Württemberg, Germany) have made the Middle Triassic of southern Germany one of the richest Triassic tetrapod fossillagerstätten worldwide. In the course of the present project, research focused on small diapsid reptiles with particular emphasis on the early evolution of Lepidosauromorpha. These studies were enabled by focused high-precision preparation, stacked microphotography and microtomography, with subsequent segmentation of CT data. These data provided insight into skull anatomy and tooth emplacement which proved to be essential for the understanding of diapsid diversity in the Vellberg fauna, as well as character evolution in the studied lepidosauromorphs and archosauriforms. In addition to the previously described Fraxinisaura and the geologically most ancient rhynchocephalian, we identified nine new taxa in the sample of small reptile remains from Vellberg: (1) tiny 8 cm long lepidosauromorph Vellbergia bartholomaei, (2) 50 cm long, omnivorous archosauriform Polymorphodon adorfi, (3) fragmentarily known palisade-toothed diapsid Stauromatodon mohli, (4) durophagous (potential lepidosauromorph) diapsid Quasicolognathus eothen, (5) a tiny new trilophosaurid archosauromorph and (6)-(9) four new lepidosaurmorph taxa that are yet to be named. Altogether, these new taxa highlight an unprecedented diversity of small saurian diapsids in the German Middle Triassic, among which seven taxa represent early relatives of Lepidosauria; the enigmatic genera Stauromatodon and Quasicolognathus may well also fall within Lepidosauromorpha, but a more confident phylogenetic placement requires better fossil evidence. The highly diversified and specialized dentitions of the new taxa indicate the existence of a rich terrestrial paleoecosystem preserved in the Vellberg fauna. At the same time, the tiny size of many of these taxa (and others described previously) has been discussed as evidence of a Lilliput Effect that, despite the late age of the Vellberg fauna relative to the P-T boundary, may have been caused by the unfavorable, arid conditions in the Central European Basin.
Publications
- 2020. A new archosauriform reptile with distinctive teeth from the Middle Triassic (Ladinian) of Germany. Journal of Vertebrate Paleontology, 40, e1764968
Sues, H.-D., Schoch, R. R., Sobral, G. and Irmis, R. B.
(See online at https://doi.org/10.1080/02724634.2020.1764968) - 2020. A tiny new Middle Triassic stemlepidosauromorph from Germany: implications for the early evolution of lepidosauromorphs and the Vellberg fauna. Scientific Reports, 10, 2273
Sobral, G., Simões, T.R. & Schoch, R.R.
(See online at https://doi.org/10.1038/s41598-020-58883-x) - 2021. A new diapsid with a unique tooth structure from the Middle Triassic (Ladinian) of Germany. Journal of Vertebrate Paleontology, e1929268
Sobral, G., Sues, H.-D. and Schoch, R. R.
(See online at https://doi.org/10.1080/02724634.2021.1929268) - 2021. A new early-diverging sphenodontian (Lepidosauria, Rhynchocephalia) from the Upper Triassic of Virginia, U.S.A. Journal of Paleontology, 95, 344 350
Sues, H.-D. and Schoch, R. R.
(See online at https://doi.org/10.1017/jpa.2020.87) - 2021. Amphibien und Reptilien der Germanischen Trias. In: Hauschke, N., Franz, M. and Bachmann, G. H. (eds): Trias. Aufbruch in das Erdmittelalter, vol. 1, pp. 324 340. Verlag Dr. Friedrich Pfeil, München
Schoch, R. R.
- 2021. Wirbeltierlagerstätten im Unteren Keuper Nordwürttembergs. In: Hauschke, N., Franz, M. and Bachmann, G. H. (eds): Trias. Aufbruch in das Erdmittelalter, vol. 2, pp. 438 440. Verlag Dr. Friedrich Pfeil, München
Schoch, R. R. and Seegis, D.
- 2022. An unusual Colognathus-like reptile from the Middle Triassic (Ladinian) Erfurt Formation of Germany. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen, 303, 227 238
Sues, H.-D., Kligman, B. T. and Schoch, R. R.
(See online at https://doi.org/10.1127/njgpa/2022/1046) - 2022. Eifelosaurus triadicus Jaekel, 1904, a forgotten reptile from the Upper Buntsandstein (Triassic: Anisian) of the Eifel region, Germany. PalZ
Sues, H.-D., Ezcurra, M. D. and Schoch, R. R.
(See online at https://doi.org/10.1007/s12542-021-00584-5)
