Archaeocyon
Archaeocyon is an extinct genus of the Borophaginae subfamily of canids native to North America. It lived during the Oligocene epoch 32-24 Ma., existing for approximately. Species of Archaeocyon are among the earliest known borophagines, although a species of Otarocyon has a slightly earlier first appearance. Fossils have been found across the northern Great Plains and along the west coast of North America.
Archaeocyon was a comparatively small and unspecialized dog. Its dentition suggests a slightly more hypocarnivorous diet than the otherwise similar Hesperocyon. The skeleton is also generalized, lacking specializations for running and retaining a plantigrade foot posture.
A few derived features of the dentition support a relationship to Borophaginae and Caninae, rather than to the basal canid subfamily Hesperocyoninae. The temporal position of Archaeocyon suggests an affinity to borophagines because the first members of Caninae appear substantially earlier.