Proterochersidae is an extinct family of

stem Stem or STEM most commonly refers to: * Plant stem, a structural axis of a vascular plant * Stem group * Science, technology, engineering, and mathematics Stem or STEM can also refer to: Language and writing * Word stem, part of a word respon ...

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

s belonging to 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 excluding ''Odontochelys'' and ''Eorhynchochelys,'' which are pla ...

List of genera

There are four genera: * ''

Chinlechelys ''Chinlechelys'' ( meaning ''Chinle turtle'') is an extinct genus of stem-turtle belonging to Testudinata. It lived in the Norian age of the Late Triassic and is the oldest turtle known from North America. Among turtles it is unique, mostly becau ...

'' Joyce ''et al.'', 2009 ** '' Chinlechelys tenertesta'' Joyce ''et al.'', 2009 * '' Keuperotesta'' Szczygielski & Sulej, 2016 (junior

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''Proterochersis''?) ** '' Keuperotesta limendorsa'' Szczygielski & Sulej, 2016 * ''

Proterochersis ''Proterochersis'' is an extinct genus of turtle from the Late Triassic period (Norian stage) of Europe. It is known from a large number of fossils uncovered in Germany and Poland.Fraas E (1913)"''Proterochersis'', eine pleurodire Schildkröte au ...

'' Fraas, 1913 ** ''Proterochersis intermedia'' Fraas, 1913 (synonym of ''P. robusta''?) ** '' Proterochersis porebensis'' Szczygielski & Sulej, 2016 ** '' Proterochersis robusta'' Fraas, 1913 * '' Thaichelys'' Szczygielski ''et al.'', 2025 ** '' Thaichelys ruchae'' (Broin, 1984)

References

Testudinata Taxa named by Franz Nopcsa von Felső-Szilvás Prehistoric reptile families {{paleo-turtle-stub