| Meridiungulata Temporal range:
| |
|---|---|
| |
| Toxodon, a notoungulate | |
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| Thesodon, a litoptern | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Infraclass: | Placentalia |
| Clade: | †Meridiungulata McKenna 1975 |
| Orders | |
South American native ungulates, commonly abbreviated as SANUs, are extinct ungulate-like mammals that were indigenous to South America from the Paleocene (from at least 63 million years ago) until the end of the Late Pleistocene (~12,000 years ago). They represented a dominant element of South America's Cenozoic terrestrial mammal fauna prior to the arrival of living unguate groups in South America during the Pliocene and Pleistocene as part of the Great American Interchange. They comprise five major groups conventionally ranked as orders—Astrapotheria, Litopterna, Notoungulata, Pyrotheria, and Xenungulata—as well as the primitive "condylarth" groups Didolodontidae and Kollpaniinae. It has been proposed that some or all of the members of this group form a clade, named Meridiungulata, though the relationships of South American ungulates remain largely unresolved. The two largest groups of South American ungulates, the notoungulates and the litopterns, were the only groups to persist beyond the mid Miocene. Only a few (mostly large) species of notoungulates and litopterns survived until the end-Pleistocene extinction event around 12,000 years ago where they became extinct with most other large mammals in the Americas, shortly after the first arrival of humans into the region.
Though most SANUs lived in South America, astrapotheres and litopterns are known from Eocene aged deposits in the Antarctic Peninsula[1] and the notoungulate Mixotoxodon spread as far north as what is now Texas during the Pleistocene as part of the Great American Biotic Interchange.[2]
The relationships of SANUs to living mammals has been historically uncertain, though analysis of DNA and collagen suggests that at least notoungulates and litopterns are members of Laurasiatheria, and closely related to living perissodactyls.