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 12.7 million years.
Species taxanomy provided by GBIF Secretariat (2022). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2023-06-13; License: CC BY 4.0