Notharctus fossil map
Where fossils of Notharctus have been found, shown on the Earth as it looked about 45 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 45 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 | 56–39.7 million years ago (Ypresian to Bartonian) |
| Periods | Paleogene |
| Family | Notharctidae |
| Named by | Leidy 1870 |
| Fossil records | 214 occurrences at 25 locations (PBDB) |
| Found in | United States |
| Rock formations | Bridger, Wasatch, Wind River, txn:91590, Aycross, Washakie |
About Notharctus
Notharctus is a genus of adapiform primate that lived in North America during the early to middle Eocene. Known from many geologic formations, including the Bridger Basin and the Devil's Graveyard Formation, Notharctus was wide-ranging throughout North America.
The genus contains at least 4 species. Notharctus is among the first known fossil primates from North America, with the first fossil being collected by Joseph Leidy from the Fort Bridger Basin in 1870. Notharctus has a long classification history involving frequent reassessment and assignment to various mammal groups, including the obsolete Pachydermata and the Mesodonta. Notharctus belonged to an extinct primate group known as Adapiformes.
Text in “About” is quoted from the Wikipedia article Notharctus (revision 1377518885), 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: Q2086632.
