Eosimias fossil map
Where fossils of Eosimias 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 | 56–33.9 million years ago (Ypresian to Priabonian) |
| Periods | Paleogene |
| Family | Eosimiidae |
| Named by | Beard et al. 1994 |
| Fossil records | 12 occurrences at 6 locations (PBDB) |
| Found in | China |
| Rock formations | Heti, txn:58156, Houldjin, Ulan Gocho, Hedi |
About Eosimias
Eosimias is a genus of early primates, first discovered and identified in 1999 from fossils collected in the Shanghuang fissure-fillings of Liyang, the southern city of Jiangsu Province, China. It is a part of the family Eosimiidae, and includes three known species: Eosimias sinensis, Eosimias centennicus, and Eosimias dawsonae. Eosimias has a skeletal structure similar to that of the common ancestor of the Haplorhini (including all simians). The name Eosimias is designed to mean "dawn monkey", from Greek eos "dawn" and Latin simius "monkey".
Dating has proven this genus lived from 45 to 40 million years ago in the middle Eocene. The genus Eosimias is unique because of the presence of primitive and derived traits. It provides new insight into the phylogenetic relationships between simians and prosimians (especially the phylogenetic position of the haplorhine prosimian tarsiers). It can best be described as a likely tree dweller with a diet consisting of insects and nectar.
Text in “About” is quoted from the Wikipedia article Eosimias (revision 1379645359), 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: Q135069.
