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. 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).

Taxonomy

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.

Phylogeny

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