Editing Moropus (section)

=== Early history ===
The first of the remains currently assigned to ''Moropus'' was a partial right [[maxilla]] (YPM 10030), uncovered at some point prior to 1873. In that year, the specimen was described YPM 10030, initially mistakenly attributed ''to Lophiodon''.<ref>{{Cite book |last=Leidy |first=Joseph |url=https://www.biodiversitylibrary.org/bibliography/61805 |title=Contributions to the extinct vertebrate fauna of the western territories |date=1873 |publisher=Govt. Print. Off |location=Washington}}</ref> After its discovery, multiple more complete specimens were discovered in the [[Miocene]] strata of the [[John Day Fossil Beds National Monument|John Day Fossil Beds]] of Oregon.<ref name=":0">{{Cite journal |last1=Holland |first1=William Jacob |author-link1=William Jacob Holland |last2=Peterson |first2=Olof August |date=1913 |title=The osteology of the Chalicotheroidea with special reference to a mounted skeleton of Moropus elatus Marsh, now installed in the Carnegie museum |url=https://www.biodiversitylibrary.org/part/211102 |journal=Memoirs of the Carnegie Museum |volume=3 |issue=2 |pages=189––406 |doi=10.5962/p.211102|doi-access=free }}</ref> In 1877, [[Othniel Charles Marsh]] formally described the specimens, assigning to them the genus name ''Moropus''. The type species of ''Moropus'', ''M. distans'', was based only on fragments of the hind foot.<ref name=":0" /><ref name=":1">{{Cite journal |last=Marsh |first=Othniel Charles |author-link=Othniel Charles Marsh |date=1877 |title=Notice of Some New Vertebrate Fossils |url=https://marsh.dinodb.com/marsh/Marsh%201877%20-%20Notice%20of%20some%20new%20vertebrate%20fossils.pdf |journal=American Journal of Science |volume=81 |issue=81 |pages=249–256|doi=10.2475/ajs.s3-14.81.249 |bibcode=1877AmJS...14..249M }}</ref> Two other species, ''M. elatus'' and ''M. senex'', were also described. At first, Marsh believed that ''Moropus'' belonged to the order [[Xenarthra|Edentata]], which historically included any mammal that lacked [[incisor]] teeth. Though he noted affinities with the African ''[[Ancylotherium]]'', he opted to erect a new [[Family (biology)|family]], Moropodidae, to exclusively include ''Moropus''.<ref name=":1" /> In 1908, geologist and palaeontologist [[Erwin Hinckley Barbour]] noted that ''Moropus'' had occasionally been treated as a form intermediate between edendates and [[Ungulate|ungulates]], though affirmed that it was definitely a true ungulate.<ref name=":2">{{Cite journal |last=Barbour |first=Erwin |date=1908-01-01 |title=The Skull of Moropus |url=https://digitalcommons.unl.edu/conservationsurvey/864/ |journal=Conservation and Survey Division}}</ref>

In 1913, Olof August Peterson named a new species of ''Moropus'', ''M. hollandi'', from limb elements recovered in 1901, at first mistakenly assigned to ''M. elatus''.<ref>{{Cite journal |last=Peterson |first=O. A. |date=1913-11-07 |title=A New Species of Moropus ( M. hollandi ) from the Base of the Middle Miocene of Western Nebraska |url=https://www.science.org/doi/10.1126/science.38.984.673.a |journal=Science |language=en |volume=38 |issue=984 |pages=673–680 |doi=10.1126/science.38.984.673.a |pmid=17732680 |issn=0036-8075|url-access=subscription }}</ref> In a 1913 [[monograph]] on chalicothere taxonomy, ''Moropus'' in particular, Peterson and [[William Jacob Holland]] recognised two additional species, ''M. matthewi'' and ''M. merriami'', and reassigned ''Moropus'' to [[Chalicotheriidae]].<ref name=":0" />