Synonyms: Aftonius calvini Hay 1913, Euceratherium americanum Gidley 1913, Euceratherium bizzelli Stovall 1937, Euceratherium sinclairi Furlong 1905, Preptoceras sinclairi Furlong 1905, Taurotragus americanus Gidley 1913
Sister taxa: none
- Euceratherium collinum: UCMP 8751, a skull. Its type locality is Potter Creek Cave, which is in a Pleistocene cave horizon in California.
- Aftonius calvini:
- Euceratherium bizzelli: Univ. Oklahoma Museum of Geology and Paleontology 701, a partial skull (crown of a skull with horns). Its type locality is Hydro, which is in a Pleistocene terrestrial gravel in Oklahoma.
- Preptoceras sinclairi:
- Taurotragus americanus: USNM 7622, a maxilla (upper right cheek teeth except P2/). Its type locality is Cumberland Cave, which is in an Irvingtonian cave horizon in Maryland.
Ecology: ground dwelling grazer-browser
Average measurements (in mm): m1 26.0 x 17.8