Scelidotheriidae

Casali, Daniel M, Boscaini, Alberto, Gaudin, Timothy J & Perini, Fernando A, 2022, Reassessing the phylogeny and divergence times of sloths (Mammalia: Pilosa: Folivora), exploring alternative morphological partitioning and dating models, Zoological Journal of the Linnean Society 196 (4), pp. 1505-1551 : 1523

Scelidotheriidae

PP = 100, age = 21.28 Mya (18.99–23.42).

This taxon, which is composed of the clades Nematheriinae and Scelidotheriinae , was recovered in all H and UN model analyses, and in some A models, and par_EW and par_IW100 topologies. For other A models, Nematheriinae was recovered as sister to ( Scelidotheriinae ( Mylodontinae (stem mylodontoids))), whereas for par_IW10 and par_IW5 analyses, it was recovered as sister to the clade uniting Scelidotheriinae and Mylodontinae .

Scelidotheriidae was supported by 21 synapomorphies (seven for both methods and 14 exclusively for BI): long axis of molariforms oblique to toothrow along its entire length; molariform morphology of Cf1/cf1 (BI); subtriangular cf1 cross-section (BI); ellipsoid mf1 cross-section (BI); subtriangular Mf2 and Mf3 cross-section (BI); S-shaped mf3 crosssection (BI); presence of a medial ridge running along anterior edge of coronoid process (BI); presence of symphysial keel (BI); snout length greater than, but no more than twice its width; uniform snout in dorsal view; large supraoccipital exposure on cranial roof, expanded anteriorly at midline; absence of fossa at the anterior edge of maxilla, lateral to external nares; equivalent anterior extent of lateral and medial palatal processes of maxilla (BI); external occipital protuberance immediately posterior to dorsal nuchal crest (BI); circular shape of ectotympanic in lateral view (BI); lateral process of entotympanic extending above anterior portion of tympanic, forming a portion of the roof of tympanic cavity (BI); promontorium dorsoventrally elongate, flat anteriorly and globose posteriorly (BI); deltoid crest facing anteriorly, reaching the medial side of the humerus in anterior view; humeral head widely exposed, raised above the tubercules (BI); posterior end of pubic cornu reaching half of anteroposterior length of acetabulum, less extended than ischiatic cornu (BI); and concave cuboid facet of astragalus.