Ctenochelyidae is an extinct family 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 ...

s which lived in

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

during the

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya ( million years ago) and 83.6 ± 0.7 m ...

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

stages of the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

Classification

The family is defined as a monophyletic clade arising from the most recent ancestors of ''

Ctenochelys ''Ctenochelys'' (meaning "comb tortoise") is an extinct genus of marine turtle ( Cryptodira, Ctenochelyidae), which existed during the Cretaceous period, and lived in the shallow waters of the Western Interior Seaway. Its fossils have been foun ...

'' and ''

Peritresius ''Peritresius'' is an extinct genus of sea turtle from the Late Cretaceous deposits in the US Eastern Seaboard. Taxonomy Two species are known, ''Peritresius ornatus'' (Leidy, 1856) and ''P. martini'' Gentry, Parham, Ehret, and Ebersole, 2018, b ...

''. Fossils of ctenochelyids are known from the

Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, or the Western Interior Sea) was a large inland sea (geology), inland sea that existed roughly over the present-day Great Plains of ...

and

Mississippi embayment The Mississippi embayment is a physiographic feature in the south-central United States, part of the Mississippi Alluvial Plain. It is essentially a northward continuation of the fluvial sediments of the Mississippi River Delta to its conflu ...

. As of 2025, four genera have been assigned to this family: ''

Asmodochelys ''Asmodochelys'' is an extinct genus of sea turtle which lived in North America during the Late Cretaceous (Campanian-Maastrichtian). Two species are known from the southern United States: ''A. parhami'' from the Demopolis Chalk The Demopolis C ...

'', ''

'' and ''

Prionochelys ''Prionochelys'' is an extinct genus of pancheloniid from the Mooreville Chalk and Eutaw Formations of Alabama. It consists of a single species, ''P. matutina''. Taxonomy ''Prionochelys'' was originally assigned to the family Toxochelyidae ...

''. Below is a

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

from the analysis by Gentry, Ebersole & Kiernan (2019):

References

{{Taxonbar, from=Q134542571 Late Cretaceous reptiles of North America Late Cretaceous turtles Prehistoric turtle stubs Chelonioidea Turtle families Extinct turtles Santonian first appearances Maastrichtian extinctions