''Euclastes'' 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 ...

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 that survived the Cretaceous–Paleogene mass extinction. The genus was first named by

Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontology, paleontologist, comparative anatomy, comparative anatomist, herpetology, herpetologist, and ichthyology, ichthyologist. Born to a wealthy Quaker fam ...

in 1867, and contains three species. ''E. hutchisoni'', was named in 2003 but has since been reassigned to the genus '' Pacifichelys'', while ''E. coahuilaensis'' named in 2009 was reassigned as '' Mexichelys coahuilaensis'' in 2010.

Description

Unlike the sea turtles '' Toxochelys'' and '' Eochelone'', ''Euclastes'' has a

secondary palate The secondary palate is an anatomical structure that divides the nasal cavity from the oral cavity in many vertebrates. In human embryology, it refers to that portion of the hard palate that is formed by the growth of the two palatine shelves med ...

. However, the secondary palate of ''Euclastes'' is not as extensive as it is in '' Ctenochelys'' and '' Angolachelys''. The genus can be distinguished by later sea turtles based on its broad, low skull; broad, flat palate; wide, flat dentary bone with an elongated symphysis; and low tomial ridge on the beak. The widened palate and dentaries give ''Eochelone'' wide, flat jaws suitable for crushing hard-shelled organisms.

Classification

Species

* †''E. acutirostris'' * †''E. platyops'' * †''E. wielandi''

Phylogeny

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 ...

based on Lynch and Parham (2003) and Parham and Pyenson (2010):

Distribution

Fossils of ''Euclastes'' have been found in: ;Maastrichtian * Bentiaba, AngolaMateus, O., M. J. Polcyn, L. L. Jacobs, R. Arujo, A. S. Schulp, J. Marinheiro, B. Pereira and D. Vineyard. 2012. Cretaceous amniotes from Angola: dinosaurs, pterosaurs, mosasaurs, plesiosaurs, turtles. Actas de V Jornadas Internacionales sobre Paleontologia de Dinosaurios y su Entorno, Salas de los Infantes, Burgos 71-105 * Quiriquina Formation, Chile * Hornerstown and Navesink Formations, New Jersey ;Paleocene * Jagüel and Roca Formations, Argentina * Aquia and Brightseat Formations, Maryland * Sidi Chennane and Couche 2 Formation, Morocco ;Eocene * Parkers Ferry Formation, South Carolina

References

External links

www.scistp.org
{{Taxonbar, from=Q5406057 Chelonioidea Prehistoric turtle genera Cretaceous–Paleogene boundary Maastrichtian genus first appearances Eocene genus extinctions Cretaceous turtles Paleocene turtles Eocene turtles Late Cretaceous reptiles of Africa Fossils of Angola Late Cretaceous reptiles of North America Cretaceous United States Fossils of the United States Late Cretaceous reptiles of South America Cretaceous Chile Fossils of Chile Paleogene reptiles of Africa Fossils of Morocco Paleogene reptiles of North America Paleogene United States Paleogene reptiles of South America Paleogene Argentina Fossils of Argentina Fossil taxa described in 1867 Taxa named by Edward Drinker Cope