Aplodontia fossil map
Where fossils of Aplodontia have been found, shown on the Earth as it looked about 0 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 0 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 | 9.4 million years ago to the present (Tortonian to Holocene) |
| Periods | Neogene, Quaternary |
| Family | Aplodontiidae |
| Named by | Richardson 1829 |
| Fossil records | 18 occurrences at 7 locations (PBDB) |
| Found in | United States |
| Rock formations | txn:41453, McKay |
About Aplodontia
The mountain beaver (Aplodontia rufa) or sewellel is a North American rodent. It is the only living member of its genus, Aplodontia, and family, Aplodontiidae. It should not be confused with true North American and Eurasian beavers, to which it is not closely related; the mountain beaver is instead more closely related to squirrels. There are seven subspecies of mountain beaver, six of which are found in California and three of which are endemic to the state.
Text in “About” is quoted from the Wikipedia article Mountain beaver (revision 1364738152), 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: Q503813.
