Trionychia is a superfamily of

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 which encompasses the

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

that are commonly referred to as softshelled turtles as well as some others. The group contains two families, Carettochelyidae, which has only one living species, the pig-nosed turtle (''Carettochelys insculpta'') native to New Guinea and Northern Australia, and

Trionychidae The Trionychidae are a taxonomic family of a number of turtle genera, commonly known as softshell turtles. The family was erected by Leopold Fitzinger in 1826. Softshells include some of the world's largest freshwater turtles, though many can a ...

, the softshelled turtles, containing numerous species native to Asia, North America and Africa. These families likely diverged during the late Jurassic. The oldest known stem-trionychian is ''

Sinaspideretes ''Sinaspideretes'' is an extinct genus of turtle from the Late Jurassic of China, probably from the Shaximiao Formation. It is considered the earliest and most basal representative of the Trionychia, and is possibly the oldest known member of C ...

'' from the Late Jurassic of China.

Systematics

Except for those not assigned to a family, only living genera are listed here. *Family Carettochelyidae ** Subfamily Carettochelyinae *** Genus '' Carettochelys'' *Pan-Trionychidae ** Family PlastomenidaeOne or more basal lineages formerly believed to be a distinct family (fossil) ** Family

***Subfamily Cyclanorbinae **** Genus '' Cyclanorbis'' **** Genus '' Cycloderma'' **** Genus ''

Lissemys ''Lissemys'' is a genus of softshell turtles in the subfamily Cyclanorbinae of the Family (biology), family Trionychidae. The genus is indigenous to southern Asia. Species The genus ''Lissemys'' contains three extant species which are recognize ...

'' *** Subfamily

Trionychinae The Trionychinae are a subfamily of turtles in the family Trionychidae. Classification The subfamily has 11 extant genera: *''Amyda'' *'' Apalone'' *'' Axestemys'' *'' Chitra'' *'' Dogania'' *'' Drazinderetes'' *'' Gobiapalone'' *'' Khunnuch ...

**** Genus ''

Amyda ''Amyda'' is a genus of softshell turtles in the family Trionychidae. It contains two extant species: * ''Amyda cartilaginea'' - Asiatic softshell turtle * ''Amyda ornata'' - Southeast Asian softshell turtle Both species were formerly consid ...

'' **** Genus ''

Apalone ''Apalone'' is a genus of turtles in the family Trionychidae. Species of ''Apalone'' are native to North America. Geographic range Most ''Apalone'' species are restricted to the United States, though the range of the spiny softshell, ''A. spini ...

'' **** Genus '' Chitra'' **** Genus '' Dogania'' **** Genus '' Nilssonia'' **** Genus '' Palea'' **** Genus ''

Pelochelys ''Pelochelys'' is a genus of very large softshell turtles in the family Trionychidae. They are found from peninsular India northeast to southern China, and south to Southeast Asia and New Guinea. The species in this genus, while still being fr ...

'' **** Genus '' Pelodiscus'' **** Genus ''

Rafetus ''Rafetus'' is a genus of highly endangered softshell turtles in the family Trionychidae. It is a genus of large turtles which are found in freshwater habitats in Asia. Species According to most taxonomists, the genus ''Rafetus'' contains the fo ...

'' **** Genus ''

Trionyx ''Trionyx'' is a genus of softshell turtles belonging to the family Trionychidae. In the past many species in the family were classified in this genus, but today '' T. triunguis'', the African or Nile softshell turtle, is the only extant softshe ...

References

;Bibliography * {{Taxonbar, from=Q1877590