Agnotocastor fossil map
Where fossils of Agnotocastor 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 | 37–18.5 million years ago (Priabonian to Burdigalian) |
| Periods | Paleogene, Neogene |
| Family | Castoridae |
| Named by | Stirton 1935 |
| Fossil records | 48 occurrences at 21 locations (PBDB) |
| Found in | United States, Kazakhstan, Canada |
| Rock formations | Brule, txn:41534, Chadron, White River, Sage Creek, Arcadia |
About Agnotocastor
Agnotocastor is an extinct member of the beaver family Castoridae. Unlike its modern relative, this species took the place of muskrats in the rivers of North America during the Oligocene epoch. The earliest species is A. galushai, which is also the first reliable member of the Castoridae. It is known chiefly from North America, with a single record from Central Asia.
Text in “About” is quoted from the Wikipedia article Agnotocastor (revision 1248772693), 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: Q4693299.
