| Sphenocoelus | |
|---|---|
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| Skeletal reconstruction of Sphenocoelus sp. | |
Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Infraclass: | Placentalia |
| Order: | Perissodactyla |
| Family: | †Brontotheriidae |
| Genus: | †Sphenocoelus Osborn, 1895 |
| Species | |
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| Synonyms | |
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Sphenocoelus is an extinct genus of brontothere known from North America during the Middle Eocene.
Description
Sphenocoelus is an average-sized brontothere, with a dolichocephalic skull.23 Some specimens of Sphenocoelus bear a prominent sagittal crests, though others lack them entirely.4 The molars are long and narrow, and the third and fourth premolars have a cusp on the posterior medial (central hind) portion of the tooth.2 They bear four digits on the forefeet.5
Classification
Sphenocoelus has had a complicated classification history, with many genera being split off or lumped within the group at various times.45 Currently, Sphenocoelus is placed within Brontotheriidae.254 The genus Dolichorhinus was once considered a species of Sphenocoelus, S. hyognathus, but is now in its own genus.65
References
References
- Hodnett, John-Paul M.; Welsh, Edward T.; Santucci, Vincent L.; Tweet, Justin S. (2022). "A Middle Eocene brontothere (Mammalia; Perissodactyla; Brontotheriidae) from Yellowstone National Park, Wyoming". FOSSIL RECORD 8. New Mexico Museum of Natural History and Science. p. 211.
- Granger, Walter; Gregory, William K (1943). "A revision of the Mongolian titanotheres". Bulletin of the AMNH. 80 10. New York: American Museum of Natural History: 363–364.
- Osborn, Henry Fairfield; Peterson, Olof August (1895). "Fossil mammals of the Uinta Basin : expedition of 1894". Bulletin of the AMNH. 7 2. New York: American Museum of Natural History: 98–102.
- Mader, Bryn J. (2008-07-30). "A species level revision of Bridgerian and Uintan brontotheres (Mammalia, Perissodactyla) exclusive of Palaeosyops". Zootaxa. 1837 (1): 1–85. Bibcode:2008Zoot.18377.1.1M. doi:10.11646/zootaxa.1837.1.1. ISSN 1175-5334.
- Mihlbachler, Matthew (2008). "Species Taxonomy, Phylogeny, and Biogeography of the Brontotheriidae (Mammalia: Perissodactyla)". Bulletin of the American Museum of Natural History. 501: 1. doi:10.1206/0003-0090(2008)501[1:stpabo]2.0.co;2.
- College~bmader@qcc.cuny.edu, Bryn J. Mader~Queensborough Community (2019-02-12). "The narial morphology of Metarhinus and Sphenocoelus (Mammalia, Perissodactyla, Brontotheriidae)". Palaeontologia Electronica. Retrieved 2026-01-28.