''Euclastes'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

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, loggerhe ...

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, paleontologist, comparative anatomist, herpetologist, and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy intereste ...

in 1867, and contains three species. ''E. hutchisoni'', was named in 2003 but has since been reassigned to the genus ''

Pacifichelys ''Pacifichelys'' is an extinct genus of sea turtle from the Middle Miocene of Peru ( Pisco Formation) and California (Temblor Formation).Mexichelys coahuilaensis ''Mexichelys'' is an extinct monotypic genus of sea turtle which lived in Mexico during the Cretaceous. The only species is ''Mexichelys coahuilaensis''. ''Mexichelys'' was erected in 2010 as a replacement name for ''Euclastes ''Euclastes ...

'' in 2010.

Description

Unlike the sea turtles ''

Toxochelys ''Toxochelys'' () is an extinct genus 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. Description ''Toxochelys'' was about 2 m (6 f ...

'' and ''

Eochelone ''Eochelone'' is an extinct genus of sea turtle from the late Eocene. It was first named by Dollo in 1903. Its type species is ''E. brabantica''. References Professor Paul's Guide to Reptiles''Eochelone''in the Paleobiology Database The Paleo ...

'', ''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 ''Ctenochelys'' is an extinct genus of marine turtle (Cryptodira, Pancheloniidae), which existed during the Cretaceous period, and lived in the shallow waters of the Western Interior Seaway. Its fossils have been found in the Ripley Formation an ...

'' and ''

Angolachelys ''Angolachelys'' is an extinct genus of African eucryptodiran turtle which existed in Angola , national_anthem = "Angola Avante"() , image_map = , map_caption = , capital = Luanda , rel ...

''. The genus can be distinguished by later sea turtles based on its broad, low skull; broad, flat palate; wide, flat

dentary bone In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable ...

with an elongated

symphysis A symphysis (, pl. symphyses) is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint. # A symphysis is an amphiarthrosis, a slightly movable joint. # A growing togethe ...

; 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 ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

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 The Quiriquina Formation is a geological formation in Chile whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, David B; et al. (2004). "Dinosaur distributi ...

, Chile * Hornerstown and

Navesink Formation The Navesink Formation is a 66 to 70 mya greensand glauconitic marl and sand geological formation in New Jersey. It is known for its Cretaceous period fossil shell beds and dinosaur bones. Description The Navesink Formation, named after Nave ...

s, New Jersey ;Paleocene * Jagüel and Roca Formations, Argentina * Aquia and

Brightseat Formation The Brightseat Formation is an exposure of marine sedimentary rock beds of Upper Cretaceous/Lower Paleocene age (65 MY to 55.5 MY), in Landover, Maryland. The exposure is located at Brightseat Road between Sheriff and Landover Roads. The site is cur ...

s, Maryland *

Sidi Chennane ''Sidi'' or ''Sayidi'', also Sayyidi and Sayeedi, ( ar, سيدي, Sayyīdī, Sīdī (dialectal) " milord") is an Arabic masculine title of respect. ''Sidi'' is used often to mean "saint" or "my master" in Maghrebi Arabic and Egyptian Arabic. ...

and

Couche 2 Formation In cooking, proofing (also called proving) is a step in the preparation of yeast bread and other baked goods in which the dough is allowed to rest and rise a final time before baking. During this rest period, yeast Fermentation in food processing ...

, Morocco ;Eocene *

Parkers Ferry Formation Parkers may refer to: *Parker's, an Australian pretzels company *''Parker's Car Guides'', a British car magazine *''The Parkers ''The Parkers'' is an American television sitcom aired on UPN from August 30, 1999, to May 10, 2004. A Spin-off (med ...

, 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