Americhelydia is a clade of turtles that consists of

sea turtle Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leatherback, loggerhe ...

snapping turtle 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 '' Acherontem ...

s, the

Central American river turtle 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 Ce ...

and mud turtles, supported by several lines of molecular work. Prior to these studies some morphological and developmental work have considered sea turtles to be basal members of

Cryptodira The Cryptodira ('' el, hidden neck'') are a suborder of Testudines that includes most living tortoises and turtles. Cryptodira differ from Pleurodira (side-necked turtles) in that they lower their necks and pull the heads straight back into the ...

and kinosternids related to the trionychians in the clade Trionychoidea. Americhelydia and Testudinoidea, both clades within Durocryptodira (hardshell turtles), split a part during the early Creataceous.

References

Cryptodira {{paleo-turtle-stub