Nothrotheriops

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Nothrotheriops
Temporal range: Pleistocene–0.011
↓
Shasta ground sloth (Nothrotheriops shastense), nearly full grown, body partly mummified from bat guano in cave
Conservation status
Extinct
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Xenarthra
Family: †Nothrotheriidae
Genus: †Nothrotheriops
Hoffstetter, 1954
Species
  • †N. shastensis (Sinclair 1905)
  • †N. texanus (Hay 1916)

Nothrotheriops is a genus of Pleistocene ground sloth found in North America, from what is now central Mexico to the southern United States.[1] 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.[2]

Discovery and species

N. shastensis skull

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.[3] 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 metres (9.0 ft) from head to tail and weighed 250 kilograms (550 lb) (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 metres (20 ft) long.[4] 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).[5]

Ecology

Restoration of N. shastensis

Nothrotheriops behaved like all typical ground sloths of North and South America, feeding on various plants like the desert globemallow, cacti, and yucca. It was hunted by various local predators, like 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.[5]

Fossil and geographic range

This genus's lineage dates back to the Miocene. The ancestors of Nothrotheriops migrated to North America from South America as part of the Great American Interchange during the Blancan, about 2.6 MYA.[1] A fossil find had been described from as far north as the Canadian province of Alberta; however, this report is believed to have been mistaken.[6] The genus lived primarily in the southwestern region of the U.S., from the states of Texas and Oklahoma to California; it has also been found in Florida.[1]

Subfossil shasta dung from Rampart Cave. NPS, 1936.

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.[3] Also, Rampart Cave in Arizona has 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.[5] The most recent credible dates are about 11,000 BP.[7]

In Popular Culture

The Shasta Ground Sloth has appeared in Prehistoric America and the movie Titans of the Ice Age. It also appears in episode 1 of the BBC2 Documentary Series: Ice Age Giants.

References

  1. ↑ 1.0 1.1 1.2 PaleoBiology Database: Nothrotheriops, basic info
  2. ↑ Muizon, C. de; McDonald, H. G.; Salas, R.; Urbina, M. (June 2004). "The Youngest Species of the Aquatic Sloth Thalassocnus and a Reassessment of the Relationships of the Nothrothere Sloths (Mammalia: Xenarthra)". Journal of Vertebrate Paleontology (Society of Vertebrate Paleontology) 24 (2): 387–397. doi:10.1671/2429a. Retrieved 2009-01-29. 
  3. ↑ 3.0 3.1 Lull, S. 1929. A remarkable ground sloth. Memoirs of the Peabody Museum of Yale University, 3: 1-39.
  4. ↑ Lange, Ian M., Ice Age Mammals of North America: A Guide to the Big, the Hairy, and the Bizarre, Mountain Press Publishing Company, 2002. Pg. 83, 85
  5. ↑ 5.0 5.1 5.2 Barton Miles & Co., Prehistoric America. A journey through the Ice Age and beyond. BBC publishing, 2002. Pg 108-9.
  6. ↑ Akersten, W. A.; McDonald, H. G. (June 1991). "Nothrotheriops from the Pleistocene of Oklahoma and Paleogeography of the Genus". The Southwestern Naturalist 36 (2): 178–185. JSTOR 3671918. 
  7. ↑ Fiedal, Stuart (2009). "Sudden Deaths: The Chronology of Terminal Pleistocene Megafaunal Extinction". In Haynes, Gary. American Megafaunal Extinctions at the End of the Pleistocene. Springer. pp. 21–37. doi:10.1007/978-1-4020-8793-6_2. ISBN 978-1-4020-8792-9. 

Further reading

External links

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