This species, initially known for an isolated jaw, was later well-studied thanks to an incomplete skeleton found in 1963 in the Bighorn Basin in Wyoming. Other North American species are A. corrugatus and A. acrogenius; the some specimens of which being ascribed to the species A. mumak.
This species, initially recognized for its solitary jaw, was later extensively studied due to an incomplete skeleton found in Wyoming's Bighorn Basin. Other North American species include A. corrugatus and A. acrogenius; some specimens of which have been classified as A. mumak.