What is "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 Whitneyan and Arikareean stages) of the Oligocene epoch, living from ~33.3—20.6 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.