Rhizocyon

Rhizocyon Temporal range: early Oligocene
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Family:	Canidae
Subfamily:	†Borophaginae
Genus:	†Rhizocyon Wang, Tedford, & Taylor, 1999
Species:	†R. oregonensis
Binomial name
†Rhizocyon oregonensis (Merriam, 1906)
Range of Rhizocyon based on fossil distribution

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 6.5 million years.

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.

References

• Wang, Xiaoming., R.H. Tedford, and B.E. Taylor. 1999. Phylogenetic systematics of the Borophaginae (Carnivora, Canidae). Bulletin of the American Museum of Natural History, 243:1-391.
• Balisi, Mairin and B. Van Valkenburgh. 2020. Iterative evolution of large-bodied hypercarnivory in canids benefits species but not clades. Communications Biology 3(461).