Abstract
Although relatively numerous accounts of late Tertiary canids have been reported from the western United States, records from Mexico are scarce. The three genera and species described and discussed in this paper come from Hemphillian and Blancan age deposits located in the state of Guanajuato, Mexico. All specimens were collected within a stratigraphic context. One taxon, Borophagus diversidens, was recovered from Blancan age deposits, while both Osteoborus cyonoides and a new species of Canis, C. ferox, came from deposits of Hemphillian age. This new species of Canis appears to be directly ancestral to the extinct C. lepophagus, long considered the forerunner of the modern coyote, C. latrans. The new Mexican canid also appears to be the earliest true Canis yet reported.
