Cynodesmus

Cynodesmus is an extinct genus of omnivorous canine which inhabited North America during the Oligocene living from 33.3—-26.3 Ma and existed for approximately .

Cynodesmus was one of the first canids to truly look dog-like. At around  in length, it was about the same size as a modern coyote, but had a shorter skull, heavier tail, and longer rump. The shape of its limbs suggests that Cynodesmus was not a very good runner compared to most other canids; it probably attacked prey from an ambush. Unlike modern dogs, it had five toes on each foot, bearing partially retractable claws.

Taxonomy 
Cynodesmus once included numerous species of Oligocene and Miocene canid with highly carnivorous (hypercarnivorous) dentitions. A revision of the genus by Wang (1994) indicates that most species previously placed in Cynodesmus are unrelated to the type species, C. thooides. These other species have been placed the genera Carpocyon, Desmocyon, Leptocyon, Metatomarctus, Osbornodon, Otarocyon, Paracynarctus, Paratomarctus, and Phlaocyon (Wang, 1994; Wang et al., 1999). Of these, only Osbornodon belongs in the same subfamily as Cynodesmus, Hesperocyoninae. The remaining genera are placed in the subfamilies Borophaginae and Caninae.

With unrelated species removed, Cynodesmus is currently restricted to the type species and the closely related C. martini (Wang, 1994).

Studies using the old conception of Cynodesmus considered it to be the ancestor of Tomarctus (16-23 Ma) from which wolves, dogs, foxes and fennecs developed. The Cynodesmus is a good example of convergent evolution because of other species such as the Borophagus, the largest and most dominant canids of the Pliocene epoch, both of which evolved from it.

Notes

References
Wang, X. 1994. Phylogenetic systematics of the Hesperocyoninae (Carnivora, Canidae). Bulletin of the American Museum of Natural History, 221:1-207.
Wang, X., R.H. Tedford, and B.E. Taylor. 1999. Phylogenetic systematics of the Borophaginae (Carnivora, Canidae). Bulletin of the American Museum of Natural History, 243:1-391.

Category:Hesperocyonines
Category:Oligocene canids
Category:Miocene canids
Category:White River Fauna
Category:Mammal genera
Category:Cenozoic mammals of North America
Category:Taxa named by William Berryman Scott
Category:Fossil taxa described in 1895