Sphenocoelus

Sphenocoelus
Temporal range: Middle Eocene
Skeletal reconstruction of Sphenocoelus sp.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Perissodactyla
Family: Brontotheriidae
Genus: Sphenocoelus
Osborn, 1895
Species
  • S. uintensis (Osborn, 1895)
Synonyms
  • Dolichorhinoides

Sphenocoelus is an extinct genus of brontothere known from North America and Asia during the Middle Eocene.[1]

Description

Sphenocoelus is an average-sized brontothere, with a dolichocephalic skull.[2][3] 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 4 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.[4][5] Currently, Sphenocoelus is placed within Brontotheriidae.[2][5][4] The genus Dolichorhinus was once considered a species of Sphenocoelus, S. hyognathus, but is now in its own genus.[6][5]

References

  1. ^ "Mindat.org". www.mindat.org. Retrieved 2025-12-02.
  2. ^ a b c 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.
  3. ^ 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.
  4. ^ a b c 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.
  5. ^ a b c d 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.
  6. ^ 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.