Macrauchenia
Macrauchenia ("long llama", based on the now-invalid llama genus, Auchenia, from Greek "big neck") is an extinct genus of large ungulate native to South America from the late Pliocene to the end of the Pleistocene. It is a member of the extinct order Litopterna, a group of South American native ungulates which had been present in South America since the early Cenozoic, over 60 million years ago, prior to the arrival of living ungulates in South America around 2.5 million years ago as part of the Great American Interchange. The bodyform of Macrauchenia has been described as similar to a camel, being one of the largest known litopterns, with an estimated body mass of around 1 tonne. The genus gives its name to its family, Macraucheniidae, which like Macrauchenia typically had long necks and three toed feet, as well a retracted nasal region, which in Macrauchenia manifests as the nasal opening being on the top of the skull behind the eye sockets. This has historically been argued to correspond to the presence of a tapir-like proboscis, but some recent authors suggest a moose-like prehensile lip is more likely.
| Macrauchenia Temporal range: | |
|---|---|
| Holotype skeleton of M. patachonica (larger) and Phenacodus primaevus (smaller) at American Museum of Natural History | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | †Litopterna |
| Family: | †Macraucheniidae |
| Subfamily: | †Macraucheniinae |
| Genus: | †Macrauchenia Owen, 1838 |
| Type species | |
| †Macrauchenia patachonica Owen, 1838 | |
| Map showing the distribution of Macrauchenia in red, and Xenorhinotherium in yellow, inferred from fossil finds | |
Only one species is generally considered valid, M. patachonica, which was described by Richard Owen based on remains discovered by Charles Darwin during the voyage of the Beagle. M. patachonica is primarily known from localities in the Pampas, but is known from remains found across the Southern Cone extending as far south as southernmost Patagonia, and as far northeast as Southern Peru. Another genus of macraucheniid Xenorhinotherium was present in northeast Brazil and Venezuela during the Late Pleistocene.
Macrauchenia became extinct as part of the end-Pleistocene extinctions around 12,000 years ago, along with the vast majority of other large mammals native to the Americas.