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| Coelurosauravus elivensis Piveteau, 1926 in Buffa, Frey, et al., 2022. Artwork: Charlène Letenneur |
ABSTRACT
The postcranial skeleton of the gliding neodiapsid reptile Coelurosauravus elivensis (Lower Sakamena Formation, ?upper Permian, southwestern Madagascar) is re-described in detail based on all previously referred specimens. The exquisite preservation of the material provides three-dimensional details of the individual bones, which are missing in the Laurasian weigeltisaurid material. A new skeletal reconstruction of C. elivensis is proposed including the first reconstruction of a weigeltisaurid reptile in lateral view. The re-examination of the material highlights interspecific differences in the postcranium of weigeltisaurids, in particular in the trunk and patagial spars. These animals have long been considered as arboreal and gliding reptiles. However, new information on the postcranium of C. elivensis reveals strong similarities with both extant and extinct quadrupeds specialized for a clinging arboreal lifestyle. Additionally, the presence of an additional phalanx in the fifth digit of the manus is now attested for all weigeltisaurids where this region is preserved. We suggest that this morphology could have allowed weigeltisaurids to grasp their patagium as observed in the extant gliding agamid Draco. Weigeltisaurids are thus the earliest known gliding vertebrates and some of the first tetrapods with an obligatory arboreal lifestyle, but also represent the only known vertebrates with a hyperphalangy aligned with a gliding apparatus.
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| Coelurosauravus elivensis Piveteau, 1926 (Madagascar, late? Permian) MNHN.F.MAP327a. A, right lateral surface of individual preserved as a natural external mold; B, silicone cast of A. Scale bar equals 10 cm. |
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| Coelurosauravus elivensis Piveteau, 1926 (Madagascar, late? Permian), lectotype MNHN.F.MAP325a. A, dorsal surface of individual preserved as a natural external mold; B, silicone cast of A. Scale bar equals 5 cm. |
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| Coelurosauravus elivensis Piveteau, 1926 (Madagascar, late? Permian), life reconstruction. Individuals clinging to Glossopteris trunk (Glossopteris leaves are associated with C. elivensis in the fossil assemblage) (Left), and gliding while grasping its wing (Right). The colors are based on the extant agamid Draco and chamaeleonid squamates. Artwork: Charlène Letenneur |
Valentin Buffa, Eberhard Frey, J.-Sébastien Steyer and Michel Laurin. 2022. The Postcranial Skeleton of the Gliding Reptile Coelurosauravus elivensis Piveteau, 1926 (Diapsida, Weigeltisauridae) from the late Permian of Madagascar. Journal of Vertebrate Paleontology. e2108713. DOI: 10.1080/02724634.2022.2108713
https://phys.org/news/2022-09-tree-canopy-evolution-first-ever-gliding.html
