Stockoceros is an extinct genus of the North American artiodactyl family Antilocapridae, known from Mexico and the southwestern United States. Its horns are each divided near their base into two prongs of roughly equal length. The genus survived until about 12,000 years ago, and was present when Paleo-Indians reached North America. One of the co-discoverers of S. onusrosagris was Quentin Roosevelt II, grandson of Theodore Roosevelt; he was 14 at the time of the discovery.