''Ctenochelys'' (meaning "comb tortoise") is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of marine turtle ( Cryptodira, Ctenochelyidae), which existed during the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

period, and lived in the shallow waters of 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 ...

. Its fossils have been found in the Ripley Formation and Mooreville Chalk of central

Alabama Alabama ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South, Deep Southern regions of the United States. It borders Tennessee to the north, Georgia (U.S. state), Georgia to the east, Florida and the Gu ...

, United States. It was first named by C. H. Sternberg in 1904, and contains two species, ''C. stenoporus'' and ''C. acris''.

Species

''Ctenochelys stenoporus'' is the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

. It was originally thought to be a species of '' Toxochelys''; ''T. bauri'', until Sternberg declared it a separate genus. The two genera are similar in

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

s. ''Ctenochelys acris'' was first named by Zangerl in 1953 and is now thought to be one of the earliest ancestors of modern cheloniids.

Phylogeny

''Ctenochelys'' in 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 of Gentry et al., 2019:

References

External links

Paleobiology DatabaseSt. Catherine's Island Sea Turtle Conservation Program: Life History: Geologic History of Sea Turtleswww.paleofile.com - Alphabetical list, Section C
Late Cretaceous turtles of North America Chelonioidea Prehistoric turtle genera {{paleo-turtle-stub