Scelidotheriidae
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 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, the enigmatic "Pseudoprepotherium", and 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. Family †Scelidotheriidae Phylogeny. The following sloth family phylogenetic tree is based on collagen and mitochondrial DNA sequence data (see Fig. 4 of Presslee "et al"., 2019).