Kinosternoidea is a

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

of aquatic

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 ...

s, which includes two families:

Dermatemydidae The Dermatemydidae are a family of turtles. The family was named by John Edward Gray in 1870, and its only extant genus is '' Dermatemys''. Subtaxa *†'' Baptemys'' *'' Dermatemys'' *†'' Gomphochelys'' *†'' Notomorpha'' References ;Bib ...

, and

Kinosternidae The Kinosternidae are a family of mostly small turtles that includes the mud turtles and musk turtles. The family contains 25 species within four genera, but taxonomic reclassification is an ongoing process, so many sources vary on the exact nu ...

. Kinosternoids are cryptodires, turtles whose necks are able to retract within their shell. Molecular studies suggest they are likely the sister group to the

snapping turtles The Chelydridae is a family of turtles that has seven extinct and two extant genera. The extant genera are the snapping turtles, '' Chelydra'' and ''Macrochelys''. Both are endemic to the Western Hemisphere. The extinct genera are ''Acherontemys ...

of the family Chelydridae. They are also

omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), a ...

, phosphatic, and actively mobile.

Classification

*Family

::*Genus ''

Dermatemys The hickatee (''Dermatemys mawii'') or in Spanish ''tortuga blanca'' ('white turtle'), also called the Central American river turtle, is the only living species in the family Dermatemydidae. The species is found in the Atlantic drainages of ...

'' ::*Genus '' Baptemys''Walter G. Joyce (2007)
Phylogenetic Relationships of Mesozoic Turtles
" Bulletin of the Peabody Museum of Natural History *Family

:*Genus ''

Hoplochelys ''Hoplochelys'' is an extinct genus of kinosternoid Kinosternoidea is a superfamily of aquatic turtles, which includes two families: Dermatemydidae, and Kinosternidae. Kinosternoids are cryptodires, turtles whose necks are able to retract wi ...

'' :*Subfamily

Staurotypinae The Staurotypinae are a subfamily of the family Kinosternidae of aquatic turtles, which contains the genera '' Claudius'' and ''Staurotypus''. ''Staurotypus'' exhibits XX/XY sex determination, in contrast to the temperature-dependent sex deter ...

::*Genus '' Claudius'' ::*Genus ''

Staurotypus ''Staurotypus'' is a genus of aquatic turtles, commonly known as giant musk turtles, Mexican musk turtles, or three-keeled musk turtles, in the family Kinosternidae. The genus contains two recognized species, which are endemic to Mexico and Cent ...

'' :*Subfamily

Kinosterninae Kinosterninae is a subfamily of the family Kinosternidae, a family of aquatic turtles. Kinosterninae contains the genera ''Kinosternon'' and ''Sternotherus'', which are native to much of the United States and northern Mexico Mexico ( Span ...

::*Genus ''

Kinosternon ''Kinosternon'' is a genus of small aquatic turtles from the Americas known commonly as mud turtles. Geographic range They are found in the United States, Mexico, Central America, and South America. The greatest species richness is in Mexi ...

'' ::*Genus ''

Sternotherus ''Sternotherus'' is a genus of turtles in the family Kinosternidae including six species commonly known as musk turtles. The genus is endemic to North America, occurring in the eastern third of the USA and southeast Ontario, Canada. Musk gland ...

Past classification

The entirely unrelated

big-headed turtle The big-headed turtle (''Platysternon megacephalum'') is a species of turtle in the family Platysternidae from Southeast Asia and southern China. Background Previously considered a distinct family placed on occasion in " Kinosternoidea", it w ...

(''Platysternon megacephalum'') was previously included in classification.

References

;Bibliography * {{Turtle-stub