''Toxochelys'' () 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 from the Late
Cretaceous period. It is the most commonly found fossilized turtle species in the
Smoky Hill Chalk, in western
Kansas
Kansas ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the west. Kansas is named a ...
.
Description
''Toxochelys'' had carapace about in length. Two species in the genus are recognized, ''Toxochelys latiremis'' and ''Toxochelys moorevillensis''.
Phylogenetic
In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...
analysis shows that ''Toxochelys'' belong to an extinct lineage of turtles transitional between modern
sea turtles and other turtles.
''Toxochelys bauri'' Williston, 1905, based on the skeleton YPM 1786, is a synonym of ''
Ctenochelys stenoporus''.
''Toxochelys'' are currently thought to be the oldest member and the last common ancestor of all extinct
marine turtles. Even though ''Toxochelys'' shared similar limb characteristics with other species as
Cheloniidae and
Protostegidae, they evolved independently to pass down new limb features to future generations. These features allowed for advanced mobility of the hand.
Phylogeny
''Toxochelys latiremis'' 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
Further reading
*Cope, E. D. 1873.
n ''Toxochelys latiremis'' ''Proceedings of the Academy of Natural Sciences of Philadelphia'' 25:10.
*Hay, O. P. 1896. On the skeleton of ''Toxochelys latiremis''. ''Publ. Field Columbian Museum, Zoological Ser''. (later ''Fieldiana: Zoology''), 1(5):101–106, pls. 14 &15.
*Case, E.C. 1898. ''Toxochelys''. The University Geological Survey of Kansas, Part IV. 4:370–385. pls. 79–84.
*Hay, O.P. 1905. A revision of the species of the family of fossil turtles called Toxochelyidae, with descriptions of two new species of ''Toxochelys'' and a new species of ''Porthochelys''. ''Bulletin of the American Museum of Natural History'' 21(10):177–185.
*Druckenmiller, P. S., A. J. Daun, J. L. Skulan and J. C. Pladziewicz. 1993. Stomach contents in the upper Cretaceous shark ''Squalicorax falcatus''. ''Journal of Vertebrate Paleontology''. 13(supplement. to no. 3):33A.
*Carrino, M.H. 2007. Taxonomic comparison and stratigraphic distribution of ''Toxochelys'' (Testudines: Cheloniidae) of South Dakota. pp. 111–132 in Martin, J.E. and Parris D.C. (eds.), ''The Geology and Paleontology of the Late Cretaceous Marine Deposits of the Dakotas''. Geological Society of America'', Special Paper 427.
*Konuki, R. 2008. ''Biostratigraphy of sea turtles and possible bite marks on a'' Toxochelys ''(Testudine, Chelonioidea) from the Niobrara Formation (Late Santonian), Logan County, Kansas and paleoecological implications for predator–prey relationships among large marine vertebrates''. Unpublished Masters thesis, Fort Hays State University, Hays, Kansas, 141 pp, Appen. I-VI.
*Matzke, A.T. 2008. A juvenile ''Toxochelys latiremis'' (Testudines, Cheloniidae) from the Upper Cretaceous Niobrara Formation of Kansas, USA. ''Neues Jahrbuch für Geologie und Paläontologie''. Abhandlungen 249(3):371–380.
*Matzke, A.T. 2009. Osteology of the skull of ''Toxochelys'' (Testudines, Chelonioidea) (with 25 text-figures). ''Palaeontographica Abteilung'' A 288(4):93–150.
External links
www.scistp.org
Chelonioidea
Late Cretaceous turtles of North America
Taxa named by Edward Drinker Cope
Fossil taxa described in 1873
Prehistoric turtle genera
Mooreville Chalk
Extinct turtles
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