The holotype specimen, AMNH 3978, was described by paleontologist and naturalist Edward Drinker Cope, who interpreted it as the rostral bone and predentary of an "agathaumid" (ceratopsid)  dinosaur, which he said came from the Laramie Formation of Colorado. It was soon thought to be a hadrosaurid, though.
The holotype specimen, AMNH 3978, initially identified by paleontologist Edward Drinker Cope as part of an "agathaumid" (ceratopsid) dinosaur from the Laramie Formation of Colorado, was later reclassified as a hadrosaurid.