| Epiaceratherium | |
|---|---|
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| Composite skull ofEpiceratherium spp. | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Perissodactyla |
| Family: | Rhinocerotidae |
| Genus: | †Epiaceratherium Abel, 1910 |
| Species | |
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Epiaceratherium is an extinct genus ofrhinocerotid from theEocene andOligocene of Europe, Asia, and North America.
The genus was named by paleontologistOthenio Abel in 1910, with the type species beingEpiaceratherium bolcense. This species is exclusively known from remains found at Monteviale in northern Italy, dating to the earliestOligocene (~34 million years ago). The speciesEpiaceratherium magnum named by Uhlig, 1999, is known from remains found in Germany, France, Czechia and Switzerland, dating to theEarly Oligocene to earlyLate Oligocene. Remains similar to this species have also been reported from Pakistan, dating to the Early Oligocene.[1] In 2013 the speciesEpiaceratherium naduongense was described from Na Duong Basin in northern Vietnam, dating to the mid-late Eocene (~39–35 million years ago).[2] In 2021, the speciesMolassitherium delemontense originally described in 2013 from late Early–early Late Oligocene deposits in Germany, Switzerland, France,[3] was reassigned toEpiaceratherium.[1]
Undescribed remains have been reported fromHaughton crater in the highCanadian Arctic likely dating to the earlyMiocene.[4]
While sometimes considered to be a member ofRhinocerotinae (and thus more closely related to living rhinoceroses than toElasmotheriinae),[5] recent phylogenetic studies have recoveredEpiaceratherium as primitivebasal rhinocerotid, outside the split betweenAceratheriinae,Elasmotheriinae andcrown groupRhinocerotinae.[1][6] Cladogram after Lu, Deng and Pandolfi, 2023:[6]
| Rhinocerotidae |
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Epiaceratherium is distinctive from other basal rhinocerotids in lacking a lower thirdincisor (i3) as well as a lowercanine, among a number of other characters of thepremolar andmolar teeth.[1] Species of the genus lacked horns.[7] The genus was relatively small in comparison to modern rhinoceroses withEpiaceratherium magnum andEpiaceratherium bolcense estimated to weigh 476–736 kilograms (1,049–1,623 lb) and 372–519 kilograms (820–1,144 lb) respectively in a 2015 study.[8] The hindfeet had three digits with hooves, while the forefeet had four, unlike modern rhinoceros.[7]