Because the name "Aublysodon mirandus" was based on the same type, it was at first a junior objective synonym of "Deinodon horridus", which latter name thus had priority. Cope in 1868 mistakenly thought the name "Deinodon" was preoccupied by the snake "Dinodon" and renamed "Deinodon horridus" into an "Aublysodon horridus". If "Deinodon" really had been preoccupied, this would have made "Aublysodon" a valid genus. In 1899 Oliver Perry Hay pointed out Cope's mistake; "Aublysodon horridus" is a junior objective synonym of "Deinodon horridus", just as "Aublysodon mirandus" had been. However, in 1892 "Aublysodon" became an independent genus when Othniel Charles Marsh further limited its type by choosing a single small nonserrated premaxillary tooth with a D-shaped cross-section, specimen ANSP 9535, as the lectotype of "Aublysodon mirandus". The two other teeth, ANSP 9533 and ANSP 9534, remained as the lectotypes of "Deinodon horridus". The names were thus separated.