| Nothrotheriops | |
|---|---|
| Shasta ground sloth (Nothrotheriops shastense), nearly full grown, partly mummified body from bat guano in cave | |
| Conservation status | |
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Fossil
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Xenarthra |
| Family: | †Megatheriidae |
| Subfamily: | †Nothrotheriinae |
| Genus: | †Nothrotheriops Hoffstetter, 1954 |
| Species | |
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Nothrotheriops is a genus of Pleistocene ground sloth found in North and South America. This genus of bear-sized xenarthran was related to the much larger, and far more famous Megatherium, although it has recently been placed in a different family, Nothrotheriidae.[1]
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Fossils of the best-known species, the Shasta ground sloth (N. shastensis), have been found throughout western North America, especially in the American Southwest. The most famous specimen was recovered from a lava tube at Aden Crater in New Mexico and was found to still have hair and tendon preserved.[2] This nearly complete specimen is on display at the Yale Peabody Museum of Natural History in New Haven, Connecticut. Numerous dung boluses belonging to Nothrotheriops have also been found throughout the southwestern United States and have provided an insight into the diet of these extinct animals.
Although N. shastensis was one of the smallest ground sloth species, it still reached 2.75 meters from head to tail and weighed 250 kg (one-quarter of a tonne) - much smaller than some of its contemporary species such as the Eremotherium, which could easily weigh over two tons and be 6 meters long.[3] It had large, stout hindlegs and a powerful, muscular tail that it used to form a supporting tripod whenever it shifted from a quadrupedal stance to a bipedal one (i.e. Eremotherium).[4]
Nothrotheriops shastensis behaved like all typical ground sloths of North and South Americas, feeding on various plants like the Desert Globemallow, cacti, and yucca. It was hunted by various local predators, like the Smilodon, from which the sloths may have defended themselves by standing upright on hindlegs and tail and swiping with their long foreclaws, like its distant relative Megatherium, as conjectured in the BBC series Walking with Beasts. The same claws could also been used as tools to reach past the plant spines and grab softer flowers and fruits. Also, the Shasta ground sloth may have had a prehensile tongue (like a giraffe) to strip leaves off branches.[4]
This species' ancestry dates back to the Miocene. Shasta ground sloths migrated to North America from South America during the Irvingtonian about 1 MYA. This species' range came as far north as the Canadian province of Alberta, making it one of the most northerly species of its clan, which otherwise lived primarity in the southern region of the North American continent, i.e. the states Texas, South Carolina and Florida.[3]
The best known historical specimen was found in a lava tube at Aden Crater in New Mexico; it was found with hair and tendon still preserved.[2] Also, prolonged period of search at Rampart Cave have revealed a plentiful amount of the sloth's hair and dung, which allowed the scientists both to use radiocarbon dating techniques to establish when it lived.[4]