Archaeotherium fossil map
Where fossils of Archaeotherium 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 | 37–16.3 million years ago (Priabonian to Burdigalian) |
| Periods | Paleogene, Neogene |
| Family | Entelodontidae |
| Named by | Leidy 1850 |
| Fossil records | 134 occurrences at 32 locations (PBDB) |
| Found in | United States, Canada |
| Rock formations | Brule, John Day, Chadron, txn:42365, White River, Cypress Hills |
About Archaeotherium
Archaeotherium (Ancient Greek: αρχαιοθήριον, meaning "ancient beast") is an extinct genus of entelodont artiodactyl endemic to North America during the Eocene and Oligocene epochs (35–28 mya). Archaeotherium fossils are most common in the White River Formation of the Great Plains, but they have also been found in the John Day Basin of Oregon and the Trans-Pecos area of Texas. Archaeotherium's fossils come from North America, between the Priabonian and Rupelian stages of the Eocene and Oligocene (35–28 million years ago). Up to fifteen species of Archaeotherium have been identified, which are divided into three subgenera. One contains the type species, A. mortoni, among others; another contains very large taxa formerly named Megachoerus and Pelonax; and the last contains A. calkinsi.
Text in “About” is quoted from the Wikipedia article Archaeotherium (revision 1380991587), 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: Q519252.
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