''Prohesperocyon'' ("before '' Hesperocyon''") is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

canid Canidae (; from Latin, ''canis'', "dog") is a family (biology), biological family of caniform carnivorans, constituting a clade. A member of this family is also called a canid (). The family includes three subfamily, subfamilies: the Caninae, a ...

, endemic to

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

appearing during the

Late Eocene The Priabonian is, in the International Commission on Stratigraphy, ICS's geologic timescale, the latest age (geology), age or the upper stage (stratigraphy), stage of the Eocene epoch (geology), Epoch or series (stratigraphy), Series. It spans ...

around 36.6 mya ( AEO).

Fossil distribution

''Prohesperocyon wilsoni'' was unearthed at the Airstrip (TMM 40504) site, Presidio County, Texas dating between 36.6 and 36.5

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

.Paleobiology Database Collection 16888
revised on 2002-06-03,

John Alroy John Alroy is a paleobiologist born in New York in 1966 and now residing in Sydney, Australia. Area of expertise Alroy specializes in diversity curves, speciation, and extinction of North American fossil mammals and Phanerozoic marine inverte ...

. This fossil species bears a combination of features that definitively mark it as a Canidae, including teeth that include the loss of the upper third molar (a general trend in canids toward a more shearing bite), and the characteristically enlarged bony bulla (the rounded covering over the middle ear). Based on what we know about its descendants, ''Prohesperocyon'' likely had slightly more elongated limbs than its predecessors, along with toes that were parallel and closely touching, rather than splayed, as in bears.

References

Eocene carnivorans Transitional fossils Monotypic prehistoric carnivoran genera Prehistoric mammals of North America Taxa named by Xiaoming Wang Fossil taxa described in 1986 {{paleo-carnivora-stub