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, loggerh ...

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 '' Acherontemys' ...

s, the Central American river turtle and

mud turtle ''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 Mexico, ...

s, 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 (') are a suborder of Testudines that includes most living tortoises and turtles. Cryptodira is commonly called the "Hidden-Neck Turtles" or the "Inside-Neck Turtles". Cryptodira differ from Pleurodira (side-necked turtles) in ...

and kinosternids related to the

trionychia Trionychia is a superfamily of turtles which encompasses the species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typic ...

ns in the clade Trionychoidea. Americhelydia and Testudinoidea, both clades within Durocryptodira (hardshell turtles), split a part during the early Cretaceous.

References

Cryptodira {{paleo-turtle-stub