Archosauria - Dinosauria - Ceratopsidae

Alternative combination: Agathaumas prorsus

Full reference: O. C. Marsh. 1890. Description of new dinosaurian reptiles. The American Journal of Science, series 3 39:81-86

Belongs to Triceratops according to N. R. Longrich and D. J. Field 2012

Sister taxon: Triceratops horridus

Type specimen: YPM 1822, a skull. Its type locality is Middle Fork, Dry Creek (YPM), which is in a Maastrichtian terrestrial sandstone/sandstone in the Laramie Formation of Wyoming.

Ecology: ground dwelling herbivore