The Recently Extinct Plants and Animals Database


Megalonyx jeffersonii Wistar, 1822 (Desmarest, 1822?)

Jefferson's ground sloth



Taxonomy & Nomenclature



Conservation Status

Last Record: 11,235 ± 40 14C yr BP = 13,180–13,034 cal yr BP (McDonald et al. In Press)



USA (New Mexico & Oklahoma)












Baghai-Riding, Nina L., Husley, Danielle B., Beck, Christine and Blackwell, Eric. (2017). Late Pleistocene megafauna from Mississippi alluvium plain gravel bars. Paludicola 11(3): 124-147. [automatic download]

Bravo-Cuevas, Victor Manuel and Jiménez-Hidalgo, Eduardo. (2018). Advances on the Paleobiology of Late Pleistocene mammals from central and southern Mexico, pp. 277-313. In: Huard, Gaeten and Gareau, Jeannine (eds.). The Pleistocene: Geography, Geology, and Fauna. New York: Nova Science Publishers.

Czaplewski, Nicholas J., Rogers, Kyler J. and Russell, Clayton. (2018). Late Pleistocene vertebrates from Three-Forks Cave, Adair County, Oklahoma Ozark Hiughland. Journal of Cave & Karst Studies 80(2): 1-16. [Abstract]

Dalquest, Walter W. (1977). Mammals of the Holloman Local Fauna, Pleistocene of Oklahoma. Southwestern Naturalist 22: 255-268.

Faith, J.T., Surovell, T.A., 2009. Synchronous extinction of North America's Pleistocene mammals. Proc. Natl. Acad. Sci. U. S. A. 106, 20641-20645.

Faunmap working group. 1994 FAUNMAP: a database documenting late Quaternary distributions of mammal species in the United States. Illinois State Museum Scientific Papers 25(1-2), 1-690.

Fernicola, J. C., Vizcaino, F, and de Iuliis, G. (2009). The Fossil Mammals collected by Charles Darwin in South America during his travels on board the HMS Beagle. Revista de la Asociatión Geológica Argentina 64(1): 147-159.

Ferrusquía-Villafranca I., Arroyo-Cabrales J., Martínez-Hernández E., Gama-Castro J., Ruiz-González J., Polaco O.J., Johnson E. 2010 Pleistocene mammals of Mexico: A critical review of regional chronofaunas, climate change response and biogeographic provinciality. Quaternary International 217(1-2): 53-104.

Gillette, D. D., McDonald, H. Gregory and Hayden, M. C. (1999). Thee first record of Jefferson’s Ground Sloth, Megalonyx jeffersonii, in Utah (Pleistocene, Rancholabrean Land Mammal Age): Utah Geological Survey Miscellaneous Publication 99(1): 509-521.

Grass, Andy Darrell. (2014). Inferring lifestyle and locomotor habits of extinct sloths through scapula morphology and implications for convergent evolution in extant sloths. PhD (Doctor of Philosophy) thesis, University of Iowa.

Harris, Arthur H. (1993). Quaternary vertebrates of New Mexico, pp. 179-197. In: Vertebrate Paleontology in New Mexico, New Mexico Museum of Natural History, Bulletin 2: i-vii, 1-338.

Hemmings, E. T. (1982). Vertebrate Fossils from Recent Red River Point Bars and Channel Bar Deposits in the Great Bend Region. Contr. Archeol. Great Bend Region 22: 30-38.

Hoganson, John W. and McDonald, H. Gregory. (2007). First Report of Jefferson’s Ground Sloth (Megalonyx Jeffersonii) in North Dakota: Paleobiogeographical and Paleoecological Significance. Journal of Mammalogy 88(1): 73-80.

Hughes, Jonathan J. (2016). Resolving the xenarthran phylogeny using nuclear loci. Thesis, McMaster University. xi + 73 pp.

Jefferson, Thomas. (1799). A memoir on the discovery of certain bones of a quadruped of the clawed kind in the western parts of Virginia. Transactions of the American Philosophical Society 4: 246-250.

Kurtén, B., and E. Anderson. 1980. Pleistocene mammals of North America. Columbia Univ. Press, New York, 442 pp.

McDonald, H. Gregory. (1996). Biogeography and Paleoecology of Ground Sloths in California, Arizona and Nevada. SBCMA Quarterly 43(1): 61-65.

McDonald, H. G., L. D. Agenbroad, and C. M. Haden. 2004. Late Pleistocene mylodont sloth Paramylodon harlani (Mammalia: Xenarthra) from Arizona. Southwestern Naturalist 49(2): 229-238.

McDonald, H. Gregory, Feranec, Robert S. and Miller, Norton. (In Press, 2018). First record of the extinct ground sloth, Megalonyx jeffersonii, (Xenarthra, Megalonychidae) from New York and contributions to its paleoecology. Quaternary International. [Abstract]

McDonald, H. Gregory, Harrington, C. R. and De Iuliis, G. (2000). The Ground Sloth Megalonyx from Pleistocene Deposits of the Old Crow Basin, Yukon, Canada. Arctic 53(3): 213-220. [Abstract]

McDonald, H. Gregory and De Iuliis, G. (2008). Fossil history of sloths, pp. 39-55. In: Vizcaíno, S. and Loughry, W. (eds.). The Biology of the Xenarthra. Gainesville, Forida: University Press of Florida.

McDonald, H.G., Miller, W.E., and Morris, T.H., 2001, Taphonomy and significance of Jefferson’s Ground Sloth (Xenarthra: Meg-alonychidae) from Utah: Western North America Naturalist, v. 61, no. 1, p. 64–77.

McDonald, H. Gregory and Ray, C. E. (1990). The Extinct Sloth, Megalonyx (Mammalia, Xenarthra), From The United-States Mid-Atlantic Continental Shelf. Proceedings of The Biological Society of Washington
103(1): 1-5.

McDonald, H. Gregory et al. (In Press, 2015). Youngest radiocarbon age for Jefferson's ground sloth, Megalonyx jeffersonii (Xenarthra, Megalonychidae). Quaternary Research. doi:10.1016/j.yqres.2014.11.006 [Abstract]

Mead, J. I., N. J. Czaplewski, and L. D. Agenbroad. 2005. Rancholabrean (Late Pleistocene) mammals and localities of Arizona. Pp. 139-180, in (R. D. McCord, ed.) Vertebrate Paleontology of Arizona, Mesa Southwest Museum Bulletin No. 11.

Milligan, Mark and McDonald, H. Gregory. (2017). Shorelines and vertebrate fauna of Pleistocene Lake Bonneville, Utah, Idaho, and Nevada. Geology of the Intermountain West 4: 181-214.

Moore, B. (1998). Lewis & Clark and Dinosaurs. We Proceeded On 24(2): 26-28.

Redmond BG, McDonald HG, Greenfield HJ, Burr ML. (2012). New evidence for Late Pleistocene human exploitation of Jefferson’s Ground Sloth (Megalonyx jeffersonii) from northern Ohio, USA. World Archaeol. 44: 75-101.

Russell D.A., Rich F.J., Schneider V., Lynch-Stieglitz J. 2009 A warm thermal enclave in the Late Pleistocene of the South-eastern United States. Biological Reviews 84(2): 173-202.

Schubert, Blaine W. (1999). A terminal Pleistocene amphibian, reptile, and mammalian fauna, Little Beaver Cave, Missouri, U.S.A. Abstracts from the 6th CAVEPS, Perth, 7-11 July, 1997. In: Baynes, Alexander and Long, John A. (eds.). Papers in vertebrate palaeontology. Records of the Western Australian Museum Supplement 57: 416.

Schubert, Blaine W., R. W. Graham, H. G. McDonald, E. C. Grimm and T. W. Stafford, Jr. (2004). Latest Pleistocene paleoecology of Jefferson’s ground sloth (Megalonyx jeffersonii) and elk-moose (Cervalces scotti) in northern Illinois. Quaternary Research 61: 231-240.

Sellards, E. H. (1916). Human remains and associated fossils from the Pleistocene of Florida. Annual Report of the Florida Geological Survey 8: 123-160.

Smith F.A., Lyons S.K., Ernest S.K.M., Jones K.E., Kaufman D.M., Dayan T., Marquet P.A., Brown J.H., Haskell J.P. 2003 Body mass of late Quaternary mammals. Ecology 84(12), 3403-3403.

Springer, Kathleen B., Pigati, Jeffrey S. and Scott, Eric. (2017). Vertebrate Paleontology, Stratigraphy, and Paleohydrology of Tule Springs Fossil Beds National Monument, Nevada (USA). Geology of the Intermountain West 4: 55-98.

Springer, K., J. C. Sagebiel, E. Scott, C. Manker, and C. Austin. 2005. Additions to the Late Pleistocene vertebrate paleontology of the Las Vegas Formation, Clark County, Nevada. Society of Vertebrate Paleontology Annual Meeting 2003 [Poster].

Springer, K., E. Scott, C. Sagebiel, and L. K. Murray. 2009. The Diamond Valley Lake local fauna: Late Pleistocene vertebrates from inland southern California. Pp. 217-235, in Papers on geology, vertebrate paleontology, and biostratigraphy in honor of Michael O. Woodburne (L. G. Albright, III, ed.). Museum of Northern Arizona Bulletin 65, Flagstaff, Arizona.

Stock, C., and J. M. Harris. 1992. Rancho la Brea: A record of Pleistocene life in California. Natural History Museum of Los Angeles County, Science Series no. 37, 7th ed.:i-xiv + 1-113.


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