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 t ...

s in the clade Testudinata. It includes all perichelydians that are more closely related to '' Sichuanchelys'' than ''

Meiolania ''Meiolania'' ("small roamer") is an extinct genus of meiolaniid stem-turtle native to Australasia from the Middle Miocene to Late Pleistocene and possibly Holocene. It is best known from fossils found on Lord Howe Island, though fossils are know ...

'', ''

Helochelydra ''Helochelydra'' is an extinct genus of extinct stem turtle known from the Early Cretaceous (Barremian) of the Isle of Wight, southern England. Phylogeny ''Helochelydra'' is a member of the stem turtle family Helochelydridae, which is known from ...

'', or any extant turtles.

Systematics

The family Sichuanchelyidae was originally created to accommodate the Middle

Jurassic The Jurassic ( ) is a geologic period and 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 Jurassic constitutes the middle period of ...

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 "unispe ...

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