Proganochelys

Proganochelys is an extinct genus of turtles from the Late Triassic, about 210 million years ago. Its fossils show an already well-developed shell, while its skull and tail retain features unlike those of living turtles.

Testudines: Testudines is the group comprising all living turtles and their extinct descendants. Proganochelys is an early member of the turtle lineage represented by this broader group.
Proganochelys quenstedtii: Proganochelys quenstedtii is the type species of the extinct turtle genus Proganochelys. It is the species represented by the best-known material assigned to the genus.
Odontochelys: Odontochelys is an extinct Late Triassic turtle known for a plastron and a less complete carapace. Its more partial upper shell contrasts with Proganochelys’s fully developed shell.
Turtle evolution: Turtle evolution is the history of the lineage leading to modern turtles and its extinct relatives. Proganochelys is a key early point in this history, but not necessarily its earliest branch.
Turtle shell: The turtle shell is a bony structure formed from the carapace, plastron, and associated skeletal elements. Its complete shell is the most conspicuous feature of Proganochelys fossils.
Trossingen: Trossingen is a town in southwestern Germany near important Late Triassic fossil localities. Fossils of Proganochelys quenstedtii were found in the region’s Late Triassic deposits.
Eunotosaurus: Eunotosaurus is a Permian reptile with broadened ribs, proposed as an early relative of turtles. It represents a much earlier stage in hypotheses about turtle origins, before a complete shell.
Phylogenetic nomenclature: Phylogenetic nomenclature names groups based on evolutionary relationships and ancestry. Its exact placement relative to crown turtles affects how its evolutionary status is described.
Carapace: The carapace is the dorsal portion of a turtle’s shell, formed from bone and overlying scutes. Its ribs and vertebrae are incorporated into Proganochelys’s upper shell.
Stubensandstein: The Stubensandstein is a Late Triassic sandstone unit in southwestern Germany. Its deposits preserve German specimens of Proganochelys.

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