This finding could provide key information about their evolutionary history and the development of their characteristic shells. In a study published in the journal Nature , these scientists explain that the fossils, classified in the genus Pappochelys , appeared in a region that was a lake 240 million years ago, when this animal lived.
As indicated, its anatomical characteristics clearly place it in an intermediate point between two other genera of archaic turtles already known, Eunotosaurus and Odontochelys . ” Evolutionary biologists have long wondered how turtles developed their shells, ” says Hans-Dieter Sues, one of the essay’s authors and curator of Vertebrate Paleontology at the Smithsonian Institution’s National Museum of Natural History.
“In the case of Pappochelys , we observed that the belly area was protected by a variety of rod-shaped bones, some of which had fused together. We knew that at some point this state must have occurred. The investigation of the embryonic development of the current turtles pointed this out. However, it had never been observed in fossils, until now, “he says.
This advance confirms that the plastron, the ventral part of the shell, arose from the union of certain bony structures similar to ribs and part of the shoulder girdle, in what would be the shoulders. Pappochelys , which could fit into the palm of one hand, also sported other physical peculiarities, such as two cavities located behind the eye sockets on each side of the skull. Today’s turtles lack them, unlike lizards or crocodiles, which do. In the opinion of paleontologists, this suggests that they are more closely related to other modern reptiles than previously believed.
Imagen: Rainer Schoch, Stuttgart Natural History Museum
