A new Middle Triassic arboreal reptile fauna from the Voltziensandstein (Grès à Voltzia) and the recovery of forest ecosystems

• Applicant: Professor Dr. Rainer Schoch
• Subject Area: Palaeontology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 467348773

The Triassic was an important phase for the evolution of life, within which a gradual recovery of the global ecosystems after the Permian-Triassic extinction took place. During this time interval, reptiles experienced major evolutionary radiations in marine, freshwater, and terrestrial environments. One of the least understood terrestrial communities were those of forest ecosystems, which were slowly re-established by early Middle Triassic time. An exceptional suite of fossillagerstätten preserving such ecosystems is the Voltziensandstein (Grès à Voltzia) of Alsace (France). This rock sequence yielded rich floras, diverse arthropod and fish faunas, and two undescribed reptile taxa collected by Louis Grauvogel in the 20th century. One of the latter, taxon A, is present with 83 specimens, including two articulated skeletons with well-preserved skull material. This 15 cm long diapsid reptile preserves features in the limbs that are believed to correlate with arboreal climbing, and the skeletons preserve extensive integumentary structures. These include stiffened epidermal structures that might be interpreted as either display features or components of a gliding or flying apparatus.The envisioned project focuses on the reptiles of the Grès à Voltzia, their anatomy and phylogenetic position, mode of life, and ecological relations within the forest habitat. It integrates data on (1) the morphology of the new reptile taxa A and B, (2) the fossillagerstätten at which they occur, and (3) the preserved rich flora and fish, mollusc and arthropod fauna of these localities in order to understand the interactions between these highly unusual forest-dwelling reptiles and the paleoecological context in which they lived. This requires a detailed analysis and some new acquisition of the available data on the Grauvogel collection on the Grès à Voltzia. Principal goals of the project are (1) to document the morphology of the new reptile taxa A and B (including CT data), (2) elucidate their phylogenetic position, (3) examine the climbing adaptations in these taxa, (4) study the habitat and putative ecological traits of these reptiles and finally (5) analyze the function of the integumentary and skeletal structures in order to decide between the two competing hypotheses: (a) an aerial gliding mechanism or (b) an elaborate display structure.

• DFG Programme: Research Grants
• International Connection: France, USA
• Cooperation Partners: Dr. Lea Grauvogel-Stamm; Dr. Gabriela Sobral; Professor Dr. Hans-Dieter Sues