Homalodotherium

Homalodotherium is an extinct genus of South American native ungulates in the order Notoungulata. Fossils of Homalodotherium have been found in the Middle Miocene (Friasian in the SALMA classification) Santa Cruz Formation of Argentina and the Río Frías Formation of Chile. The first specimen, a partial skull, was discovered by Robert Holiver Cunningham while on an expedition to Patagonia. By the time it had arrived in England, it was degraded to the point where only a few elements remained. Regardless, in 1870, it was given its genus name by Thomas Henry Huxley, and its species name (H. cunninghami, after its discoverer) by William Henry Flower. The name was misspelled repeatedly over the years, leading to the erection of the family Homalodontotheriidae to include it, though this has since been amended to Homalodotheriidae. Since, then four more species of Homalodotherium have been named.

Homalodotherium was a fairly large animal, with a body length of and a body mass of . It had a proportionally small head with broad, flat, teeth, and, unusually for South American native ungulates, large claws on its forelimbs. Initially, it was suggested that these were used for digging. However, it is more likely that they were instead used for pulling vegetation to within the range of the mouth, which may have been supplemented by a prehensile upper lip (indicated by its retracted nasal bones). In these regards, Homalodotherium is convergent with chalicotheres, a lineage of perissodactyls that may have similarly browsed from trees.