Margery CoombsRounds, Carolyn2024-04-262010-12-1120110210.7275/1693807https://hdl.handle.net/20.500.14394/47455The chalicothere Moropus was a rare perissodactyl present in the Great Plains region of North America through much of the Miocene. A temporal gap in named species of Moropus is present in the early Hemingfordian North American Land Mammal Age. This gap is filled by specimens currently referred to as Moropus sp. from the Batesland Formation in southwest South Dakota, and unnamed specimens of Moropus in the Runningwater Formation in northwestern Nebraska. A comparison of the fossils of Moropus nsp. from the Batesland Formation with those of previously described chalicothere species from the Greats Plains region, such as Moropus elatus, Moropus hollandi, Tylocephalonyx skinneri, Moropus merriami, and Moropus matthewi, in addition to Metaschizotherium bavaricum and Metaschizotherium fraasi from the Miocene of Southern Germany, illustrates that there are substantial differences in morphology between equivalent skeletal elements. Based on these findings, I propose that the specimens of Moropus from the Batesland Formation belong to a new species.Moropusnew speciesGreat PlainsBatesland FormationMioceneBiologyEvolutionPaleobiologyPaleontologythesis