Scelidotheriidae Temporal range: Late Oligocene-Late Pleistocene (Deseadan-Lujanian) ~29–0.009 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Scelidotherium leptocephalum in Paris
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Pilosa
Superfamily:	Mylodontoidea
Family:	†Scelidotheriidae Ameghino 1889
Genera
†Analcitherium †Catonyx †Chubutherium †Nematherium †Neonematherium †Proscelidodon †Scelidodon †Scelidotheridium †Scelidotheriops †Scelidotherium †Sibyllotherium †Valgipes

Scelidotheriidae is a family of extinct ground sloths within the order Pilosa, suborder Folivora and superfamily Mylodontoidea, related to the other extinct mylodontoid family, Mylodontidae, as well as to the living two-toed sloth family Choloepodidae. The only other extant family of the suborder Folivora is the distantly related Bradypodidae. Erected as the family Scelidotheriidae by Ameghino in 1889, the taxon was demoted to a subfamily of Mylodontidae by Gaudin in 1995.^[1][2] However, recent collagen sequence data indicates the group is less closely related to Mylodon and Lestodon than Choloepus is, and thus it has been elevated back to full family status by Presslee et al. (2019).^[3]

Together with Mylodontidae, and the two-toed sloths, the scelidotheriids form the superfamily Mylodontoidea. Chubutherium is an ancestral and very plesiomorphic member of this family and does not belong to the main group of closely related genera.

The following sloth family phylogenetic tree is based on collagen and mitochondrial DNA sequence data (see Fig. 4 of Presslee et al., 2019).^[3]

Below is a more detailed cladogram of the Scelidotheriidae, based on the work of Nieto et al. 2020.^[4]

• Cuvier, G. (1796): Notice sur le squelette d'une très grande espèce de quadrupède inconnue jusqu'à présent, trouvé au Paraguay, et déposé au cabinet d'histoire naturelle de Madrid. Magasin encyopédique, ou Journal des Sciences, des Lettres et des Arts (1): 303-310; (2): 227-228.
• Iuliis, G.; Cartelle, C. (December 1999). "A new giant megatheriine ground sloth (Mammalia: Xenarthra: Megatheriidae) from the late Blancan to early Irvingtonian of Florida". Zoological Journal of the Linnean Society. 1 27 (4): 495–515. doi:10.1006/zjls.1998.0190.
• Harrington, C.R. (1993): Yukon Beringia Interpretive Center - Jefferson's Ground Sloth. Retrieved 2008-JAN-24.
• Hogan, C.M. (2008): Cueva del Milodon, Megalithic Portal. Retrieved 2008-APR-13
• Kurtén, B.; Anderson, E. (1980). Pleistocene Mammals of North America. Columbia University Press. ISBN 978-0-231-03733-4. OCLC 776120509.
• McKenna, M. C.; Bell, S. K. (1997). Classification of Mammals: Above the Species Level. Columbia University Press. ISBN 978-0-231-52853-5. OCLC 182575570.
• Nowak, R.M. (1999): Walker's Mammals of the World (Vol. 2). Johns Hopkins University Press, London.
• White, J. (1993). "Indicators of locomotor habits in xenarthrans: Evidence for locomotor heterogeneity among fossil sloths". Journal of Vertebrate Paleontology. 13 (2): 230–242. Bibcode:1993JVPal..13..230W. doi:10.1080/02724634.1993.10011502.
• White, J.L.; MacPhee, R.D.E. (2001). "The sloths of the West Indies: a systematic and phylogenetic review". In Woods, C.A.; Sergile, F.E. (eds.). Biogeography of the West Indies: Patterns and Perspectives. Boca Raton, London, New York, and Washington, D.C.: CRC Press. pp. 201–235. doi:10.1201/9781420039481-14. ISBN 978-0-8493-2001-9.
• Woodward, A. S. (January 1900). "On some Remains of Grypotherium (Neomylodori) listai and associated Mammals from a Cavern near Consuelo Cove, Last Hope Inlet, Patagonia". Proceedings of the Zoological Society of London. 69 (1): 64–78. doi:10.1111/j.1096-3642.1890.tb01704.x.

Wikimedia Commons has media related to Ground Sloth.

• Sloth World: An Online Sloth Bibliography
• Picture and information about a ground sloth skeleton on display at the University of Georgia's Science Library
• Have some ground sloths survived in Argentina?
• Ground sloths in general
• Western Center for Archaeology and Paleontology Hemet, CA

v t e Pilosan genera
Kingdom: Animalia Phylum: Chordata Class: Mammalia Superorder: Xenarthra
Pilosa Vermilingua †Argyromanis †Orthoarthrus Cyclopedidae Cyclopes †Palaeomyrmidon Myrmecophagidae Myrmecophaga †Neotamandua †Protamandua Tamandua Folivora †Pseudoglyptodon †Megalocnidae Acratocnus Imagocnus Megalocnus Mesocnus Miocnus Neocnus Parocnus Mylodontoidea Choloepus †Scelidotheriidae Analcitherium Catonyx Chubutherium Nematherium? Neonematherium Proscelidodon Scelidodon Scelidotheridium Scelidotheriops Scelidotherium Sibyllotherium Valgipes †Mylodontidae Baraguatherium Eionaletherium Nematherium Octodontobradys Octodontotherium Octomylodon Orophodon Paroctodontotherium Pseudoprepotherium Urumacotherium Mylodontinae Archaeomylodon Brievabradys? Glossotheriopsis Megabradys Mylodonopsis Ocnotherium Oreomylodon? Promylodon Ranculcus Strabosodon Lestodontini Bolivartherium Lestobradys Lestodon Magdalenabradys Sphenotherus Thinobadistes Mylodontini Glossotheridium Glossotherium Kiyumylodon Mylodon Paramylodon Pleurolestodon Simomylodon Megatherioidea see below↓
Megatherioidea Megatherioidea Bradypus †Hapalops †Hiskatherium †Hyperleptus †Pelecyodon †Schismotherium †Similhapalops †Megalonychidae Deseadognathus Hapalops? Hyperleptus? Mesopotamocnus Paulocnus Proplatyarthrus Urumacocnus Ortotheriinae Diodomus Eucholoeops Hapaloides Megalonychotherium Ortotherium Paranabradys Pliomorphus Proschismotherium Pseudortotherium Torcellia Megalonychinae Ahytherium Australonyx Megalonychops Megalonyx Megistonyx Meizonyx Nohochichak Pattersonocnus Pliometanastes Protomegalonyx Sinclairia Xibalbaonyx Zacatzontli †Megatheria Analcimorphus Nothrotheriidae Neohapalops Thalassocnus? Nothrotheriinae Amphibradys Aymaratherium Chasicobradys Huilabradys Lakukullus Mcdonaldocnus Mionothropus Nothropus Nothrotheriops Nothrotherium Pronothrotherium Xyophorus Megatheriidae Thalassocnus? Planopsinae Planops Prepotherium Prepoplanops Proprepotherium Megatheriinae Anisodontherium Diabolotherium Eomegatherium Eremotherium Megathericulus Megatheridium Megatheriops Megatherium Ocnopus Perezfontanatherium Plesiomegatherium Pliomegatherium Proeremotherium Promegatherium Pyramiodontherium Sibotherium Urumaquia