Sichuanchelyidae is a family of extinct

turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...

s in the clade

Testudinata Testudinata is the group of all tetrapods with a true turtle shell. It includes both modern turtles (Testudines) and many of their extinct, shelled relatives (stem-turtles). Though it was first coined as the group containing turtles by Jacob The ...

. It includes all perichelydians that are more closely related to '' Sichuanchelys'' than '' Meiolania'', '' Helochelydra'', or any extant turtles.

Systematics

The family Sichuanchelyidae was originally created to accommodate the Middle

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

Chinese turtle '' Sichuanchelys'', and it was considered

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

until Joyce et al. (2016) recovered the problematic Late Cretaceous turtle '' Mongolochelys'' from Mongolia as a close relative of ''Sichuanchelys''. The late Paleocene form '' Laurasichersis'' from Europe is the youngest sichuanchelyid, showing that stem turtles in Laurasia outlived the Mesozoic.

References

Extinct turtles Testudinata Prehistoric reptile families {{paleo-turtle-stub