Rhizocyon fossil map
Where fossils of Rhizocyon have been found, shown on the Earth as it looked about 30 million years ago and on today’s map.
Dots are fossil collections recorded in the Paleobiology Database. The “then” view moves today’s fossil sites back to their positions 30 million years ago (the time slice nearest the median age of the fossils) using the Merdith et al. (2021) plate model; positions are approximate. Open on the timeline map →
| Group | Early mammals |
|---|---|
| Lived | 29.5–24.7 million years ago (Rupelian to Chattian) |
| Periods | Paleogene |
| Family | Canidae |
| Named by | Wang et al. 1999 |
| Fossil records | 6 occurrences at 2 locations (PBDB) |
| Found in | United States |
| Rock formations | John Day |
About 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 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.
Text in “About” is quoted from the Wikipedia article Rhizocyon (revision 1257319438), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 23 October 2026. Ages are those of the rock layers the fossils were found in. Wikidata: Q16956581.
