Paleontologists from France and Germany have focused on the postcranial skeleton — including a remarkable gliding apparatus called the patagium — of Coelurosauravus elivensis, a neodiapsid reptile that lived in Madagascar during the Late Permian epoch, between 258 and 252 million years ago.
Life reconstruction of Coelurosauravus elivensis: individuals clinging to Glossopteris trunk (Glossopteris leaves are associated with Coelurosauravus elivensis in the fossil assemblage) and gliding while grasping its wing; the colors are based on the extant agamid Draco and chamaeleonid squamates. Image credit: Charlène Letenneur, MNHN.
Coelurosauravus elivensis belongs to the family Weigeltisauridae, a group of neodiapsid reptiles that lived during the Late Permian epoch.
Fossils of these gliding creatures have been found in Madagascar and Europe; a possible weigeltisaurid, Wapitisaurus, been found in North America.
The weigeltisaurids possessed long, hollow rod-shaped bones extending from the torso; these structures formed folding wings used for gliding flight.
“Pennsylvanian forests (323-299 million years ago), while taxonomically and vertically heterogeneous, had rather open canopy strata with spatially separated arborescent taxa resulting in little crown overlap,” said Dr. Valentin Buffa, a paleontologist with the Centre de Recherche en Paléontologie – Paris at the French Natural History Museum.
“In contrast, Cisuralian forests (299-273 million years ago) show evidence of denser communities suggestive of more continuous canopy strata.”
“Such change in forest structure could explain why no gliders have been reported prior to weigeltisaurids although several arboreal or scansorial amniotes have been described from Pennsylvanian and Cisuralian deposits.”
“These dragons weren’t forged in mythological fire — they simply needed to get from place to place. As it turned out, gliding was the most efficient mode of transport and here, in this new study, we see how their morphology enabled this.”
Coelurosauravus elivensis, lectotype: (A) dorsal surface of individual preserved as a natural external mold; (B) silicone cast of A. Scale bar – 5 cm. Image credit: Buffa et al., doi: 10.1080/02724634.2022.2108713.
In the study, Dr. Buffa and his colleagues examined three known fossils of Coelurosauravus elivensis as well as a number of related weigeltisaurids.
They focused on the postcranial skeleton, including the torso, limbs, and the patagium. The latter is the membranous flap spanning the forelimbs and hindlimbs, also found in living flying squirrels, sugar gliders, and colugos.
Previous analysis of Coelurosauravus elivensis had assumed that its patagium was supported by bones that extended from the ribs, as they do in modern Draco species of Southeast Asia.
However, the new study suggests that its patagium either extended from the gastralia — an arrangement of bones in the skin that covers the belly of some reptiles, including crocodilians and dinosaurs — or from the musculature of the trunk.
This would mean that the gliding apparatus sat lower on the abdomen than it does in modern gliding lizards.
“Sharp, curved claws and compressed body form support the idea that Coelurosauravus elivensis was perfectly adapted to moving vertically up tree trunks,” Dr. Buffa said.
“The similarity in length of the forelimbs and hindlimbs further indicate that it was an expert climber — their proportional length assisted it in remaining close to the tree’s surface, preventing it from pitching and losing its balance.”
“Its long, lean body and whiplike tail, also seen in contemporary arboreal reptiles, further supports this interpretation.”
The findings were published in the Journal of Vertebrate Paleontology.
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Valentin Buffa et al. The postcranial skeleton of the gliding reptile Coelurosauravus elivensis Piveteau, 1926 (Diapsida, Weigeltisauridae) from the Late Permian of Madagascar. Journal of Vertebrate Paleontology, published online September 8, 2022; doi: 10.1080/02724634.2022.2108713
Source link: https://www.sci.news/paleontology/coelurosauravus-elivensis-11186.html
