Rhizocyon
Rhizocyon ("root dog") is an early member of the subfamily Borophaginae, an extinct subgroup of canids that were endemic to western North America during the Oligocene epoch, living from ~31—24.5 Ma., existing for approximately . "Rhizocyon" was similar to a contemporary species, "Archaeocyon leptodus", from the Great Plains, but it shows a few subtle differences in the structure of the skull and dentition that indicate that "Rhizocyon" may be close to the ancestry of later borophagines. Only a single species, R. oregonensis, is known and all fossils come from the John Day Formation in Oregon.