Duchesneodus is a large brontothere endemic to North America. It lived during the Late Eocene 40.4âÂÂ37.2 mya, existing for approximately . The skeletal characteristic of the mammal was defined by the dome size that was sexually in two distinct forms. The females had a lower but prominent dome while the males had larger domes. Several species of Duchesneodus have been named historically, though only one is recognized as valid today, D. uintensis.