Pappochelys

Pappochelys (παπποχέλυς [πάππος (grandfather) + χέλυς (turtle)] meaning "grandfather turtle" in Greek) is an extinct genus of diapsid reptile possibly related to turtles. The genus contains only one species, Pappochelys rosinae, from the Middle Triassic of Germany, which was named by paleontologists and Hans-Dieter Sues in 2015. The discovery of Pappochelys provides strong support for the placement of turtles within Diapsida, a hypothesis that has long been suggested by molecular data, but never previously by the fossil record. It is morphologically intermediate between the definite stem-turtle Odontochelys from the Late Triassic of China and Eunotosaurus, a reptile from the Middle Permian of South Africa.

==Description== thumb|left|Life restoration Pappochelys had a wide body, small skull, and a long tail that makes up about half of the total body length, which is up to . The skull is pointed with large eye sockets. Several turtle-like features are present, including expanded ribs and gastralia that seem to be precursors of a shell. As is the case in Eunotosaurus, each rib is flattened into a broad blade-like structure with bumps and ridges covering its outer surface and a ridge running down its inner surface, forming a T-shape in cross section. The gastralia (rib-like bones covering the abdomen) are tightly packed and occasionally fused together, forming a structure similar to the plastron of turtles. Unlike turtles, Pappochelys has teeth in its jaws and two pairs of holes in the back of the skull called temporal fenestrae. The presence of two pairs of fenestrae make the skull of Pappochelys diapsid, as opposed to the anapsid skulls of turtles that lack any temporal fenestrae.