Psephochelys

Psephochelys is known from only one species, Psephochelys polyosteoderma, and the first fossil was a partial skeleton found in the Falong Formation in China.1

Unlike turtles, Psephochelys had no hard shell on its belly. Instead, it had rib-like bones and small bony plates that were loosely connected.1

A subadult specimen shows that the shell of Psephochelys grew by fusing small plates together, starting from the middle and edges, similar to how a turtle's shell develops.3

Psephochelys belonged to a group called placodonts, which were marine reptiles that looked like turtles but are not closely related to them.1

The name Psephochelys means 'pebbly turtle' because its shell was made of many small, pebble-like bony plates.1

Psephochelys lived during the Carnian age of the Late Triassic, between about 233 and 227 million years ago.2