Euclastes
Euclastes is an extinct genus of sea turtles that survived the Cretaceous–Paleogene mass extinction. The genus was first named by Edward Drinker Cope 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. 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. Phylogeny. Cladogram based on Lynch and Parham (2003) and Parham and Pyenson (2010): Distribution. Fossils of "Euclastes" have been found in: