Euclastes Explained

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,^[1] while E. coahuilaensis named in 2009 was reassigned as Mexichelys coahuilaensis in 2010.^{[2] [3]}

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.^[4] 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.^[1]

Classification

Species

• †E. acutirostris
• †E. platyops
• †E. wielandi

Phylogeny

Cladogram based on Lynch and Parham (2003)^[1] and Parham and Pyenson (2010):^[5]

Distribution

Fossils of Euclastes have been found in:^[6]

Maastrichtian

• Bentiaba, Angola^[7]
• 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

External links

• www.scistp.org

Notes and References

1. Lynch . S.C. . Parham, J.F. . 2003 . The first report of hard-shelled sea turtles (Cheloniidae sensu lato) from the Miocene of California, including a new species (Euclastes hutchisoni) with unusually plesiomorphic characters . PaleoBios . 23 . 3 . 21–35 .
2. http://paleodb.org/cgi-bin/bridge.pl?action=checkTaxonInfo&taxon_no=165647&is_real_user=0 Euclastes coahuilaensis
3. http://noticias.terra.com.br/ciencia/interna/0,,OI3618441-EI238,00-Exibidos+fosseis+de+tartarugas+com+mi+de+anos.html Exibidos fósseis de tartarugas com 72 mi de anos
4. Mateus . Octávio . Jacobs . Louis . Polcyn . Michael . Schulp . Anne S. . Vineyard . Diana . Buta Neto . André . Telles Antunes . Miguel . The Oldest African Eucryptodiran Turtle from the Cretaceous of Angola . Acta Palaeontologica Polonica . December 2009 . 54 . 4 . 581–588 . 10.4202/app.2008.0063. free .
5. Nicholas Pyenson. James F. Parham. Nicholas D. Pyenson. 2010. New Sea Turtle from the Miocene of Peru and the Iterative Evolution of Feeding Ecomorphologies since the Cretaceous. Journal of Paleontology. 84. 2. 231–247. 10.1666/09-077R.1. 2010JPal...84..231P . 62811400.
6. http://www.fossilworks.org/cgi-bin/bridge.pl?a=taxonInfo&taxon_no=67331 Euclastes
7. Mateus, 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