Oradectes

Oradectes (meaning "margin biter", from Latin ora (margin) and dectes (biter)) is an extinct genus of diadectid reptiliomorph. It is known from a single partial skeleton collected from the Early Permian Cutler Formation of Colorado in the United States. The type species, O. sanmiguelensis, was originally named as a species of Diadectes in 1965. It was given its own genus in 2010.

Oradectes Temporal range: Early Permian
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Order:	†Diadectomorpha
Family:	†Diadectidae
Genus:	†Oradectes Kissel, 2010
Species
†O. sanmiguelensis (Lewis and Vaughn, 1965 [originally Diadectes sanmiguelensis])

Description

The only material belonging to Oradectes is a partial skeleton known as MCZ 2989. This skeleton includes a complete skull, neck vertebrae, a partial pectoral girdle, the right forelimb, and some ribs. The skull is robust with spade-shaped teeth lining the jaws. The front teeth of the lower jaw protrude outward. A ventral border of the Meckelian fenestra of the lower jaw formed entirely from the splenial bone is a distinguishing feature of Oradectes found in no other diadectid.[1]

Classification

Oradectes sanmiguelensis was described by Lewis and Vaughn (1965) as a species of Diadectes, D. sanmiguelensis. In a 2005 phylogenetic study of diadectids, D. sanmiguelensis was found to be one of the most basal diadectids and was placed far from a clade containing most of the other species of Diadectes.[2] A 2010 analysis came up with the same results and assigned D. sanmiguelensis to the new genus Oradectes. Below is a cladogram from the 2010 study showing the phylogenetic position of Oradectes:[1]

Diadectomorpha	Limnoscelidae       Tseajaiidae    Diadectidae    Ambedus pusillus       Oradectes sanmiguelensis       Orobates pabsti       Desmatodon hesperis       Silvadectes absitus       Diadectes tenuitectes     Diadectes sideropelicus     Diasparactus zenos

References

1. Kissel, R. (2010). Morphology, Phylogeny, and Evolution of Diadectidae (Cotylosauria: Diadectomorpha). Toronto: University of Toronto Press. p. 185. hdl:1807/24357.
2. Kissel, R.; Reisz, R.; Berman, D. (2005). "Revisiting the taxonomy of Diadectidae (Cotylosauria: Diadectomorpha): a phylogenetic approach". Journal of Vertebrate Paleontology. 25 (Supplement 3): 78A. doi:10.1080/02724634.2005.10009942.