Tetraclaenodon fossil map
Where fossils of Tetraclaenodon have been found, shown on the Earth as it looked about 66 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 66 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 | 63.4–57.5 million years ago (Danian to Thanetian) |
| Periods | Paleogene |
| Family | Phenacodontidae |
| Named by | Scott 1892 |
| Fossil records | 100 occurrences at 18 locations (PBDB) |
| Found in | United States, Canada |
| Rock formations | Nacimiento, Fort Union, "Fort Union" (= Lebo), txn:42284, Hanna, "Fort Union No. 3" (= Melville) |
About Tetraclaenodon
Tetraclaenodon is an extinct genus of phenacodontid mammal from the Paleocene of North America. It is the oldest and least specialized member of Phenacodontidae, a family of small early ungulates (hoofed mammals). Its fossils were first reported from the Nacimiento Formation of New Mexico, though it was common and widely distributed across many western states. Compared to other phenacodontids, Tetraclaenodon was small and built for strength over speed. Its bunodont teeth, five-toed paws, and narrow hooves are more generalized than later members of its family.
A 2012 study positioned Tetraclaenodon as the basalmost member of the clade containing "Phenacodontidae" and Altungulata (a proposed grouping of perissodactyls and African ungulates). Most studies reject Altungulata as a natural grouping, though phenacodontids are still often considered close (or even ancestral) to perissodactyls.
Text in “About” is quoted from the Wikipedia article Tetraclaenodon (revision 1380250842), 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: Q24883975.
