Herpetotherium fossil map
Where fossils of Herpetotherium 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 | 56–16.3 million years ago (Ypresian to Burdigalian) |
| Periods | Paleogene, Neogene |
| Family | Herpetotheriidae |
| Named by | Cope 1873 |
| Fossil records | 464 occurrences at 85 locations (PBDB) |
| Found in | United States, Canada |
| Rock formations | Bridger, Friars, txn:58227, Wagon Bed ("Tepee Trail"), Cypress Hills, Wind River |
About Herpetotherium
Herpetotherium is an extinct genus of metatherian mammal, belonging to the possibly paraphyletic family Herpetotheriidae. Native to North America from the Eocene to Early Miocene, fossils have been found in California, Oregon, Texas, Florida, Montana, Wyoming, Colorado, North and South Dakota, Nebraska, and Saskatchewan. The oldest species, H. knighti, is dated to around 50.3 mya, and the most recent, an unnamed species, may be as recent as 15.97 mya. A morphological analysis of marsupials and basal metatherians conducted in 2007 found Herpetotherium to be the sister group to extant marsupials. It is the youngest known metatherian from North America until the migration of the Virginia opossum from South America within the last 2 million years.
Text in “About” is quoted from the Wikipedia article Herpetotherium (revision 1379605611), 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: Q601759.
