Euclastes is an extinct genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of sea turtle

Sea turtle

Sea turtles are marine reptiles that inhabit all of the world's oceans except the Arctic.-Distribution:...

. It was first named by Edward Drinker Cope

Edward Drinker Cope

Edward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen...

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

Pacifichelys

Pacifichelys is an extinct sea turtle from the Miocene of Peru and California. It was first named by James F. Parham and Nicholas D. Pyenson in 2010, and the type species is Pacifichelys urbinai from Peru. A second species, P. hutchisoni, was reassigned from the genus Euclastes. It is known from...

.

Description

Unlike the sea turtles Toxochelys

Toxochelys

Toxochelys is an extinct genus of sea turtle from the Cretaceous period. It is the most commonly found fossilized turtle species in the Smoky Hill Chalk, in western Kansas. Toxochelys was about 2 m in length...

and Eochelone

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:* * in the Paleobiology Database...

, Euclastes has a secondary palate

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 medially and their mutual fusion in the midline...

. However, the secondary palate of Euclastes is not as extensive as it is in Ctenochelys

Ctenochelys

Ctenochelys is an extinct genus of Cryptodira, which existed during the Cretaceous period, and lived in shallow waters. Its fossils have been found in the Ripley Formation in central Alabama, USA. It was first named by C.H. Sternberg in 1904, and contains four species, C. stenopora, C. acris, C....

. 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

Symphysis

A symphysis is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint.1.A symphysis is an amphiarthrosis, a slightly movable joint.2.A growing together of parts or structures...

; and low tomial ridge on the beak. The widened palate and dentaries give Eochelone wide, flat jaws suitable for crushing hard-shelled organisms.

Phylogeny

Cladogram

Cladogram

A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...

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

External links

• www.scistp.org
• Euclastes at the Paleobiology Database
  Paleobiology Database
  ' is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.-History:The Paleobiology Database was founded in 2000. It has been funded by the National Science Foundation and the Australian Research Council...