Leptomeryx fossil map
Where fossils of Leptomeryx 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 | 39.7–18.5 million years ago (Bartonian to Burdigalian) |
| Periods | Paleogene, Neogene |
| Family | Leptomerycidae |
| Named by | Leidy 1853 |
| Fossil records | 286 occurrences at 49 locations (PBDB) |
| Found in | United States, Canada, Mexico |
| Rock formations | Brule, txn:42603, White River, Chadron, Renova, Cypress Hills |
About Leptomeryx
Leptomeryx is an extinct genus of artiodactyl that lived in North America during the middle Eocene through early Miocene. One of the earliest ruminants, it belongs to the extinct family Leptomerycidae, which is related to today's chevrotains. Most fossils were found in the badlands of the Midwestern United States in sedimentary rocks of the White River Group, in the Brule and Chadron formations. Additional remains have been reported from southern Canada and Mexico. The genus was scientifically described in 1853 by Joseph Leidy and includes several species.
Leptomeryx was a cat-sized animal with a short neck and long and slender limbs. The hind limbs were much longer than the forelimbs. The upper canine tooth was not enlarged, in contrast to chevrotains. The animal probably lived in herds and feed on soft plants. During the late Eocene, the genus probably lived in forests. During the early Oligocene, it adapted to the open habitats hat became prevalent at that time and became one of the most common artiodactyls.
Text in “About” is quoted from the Wikipedia article Leptomeryx (revision 1363990238), 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: Q6528180.
