RHINOCEROTIDAE

The monophyly of Rhinocerotidae, including Trigonias osborni Lucas, 1900, Aceratherium incisivum Kaup, 1832 and Ronzotherium filholi (Osborn, 1936), is supported by eleven unambiguous synapomorphies: presence of a sagittal crest on the basilar process 44 (1); i2 is tusk-like 79 (1); i3 is absent 81 (1); c1 is absent 82 (1); p2 paralophid is isolated, spur-like 154 (0); semilunate distal border of anterior side is acute 212 (0); magnum posterior tuberosity is long 220 (1); unciform posterior expansion of the pyramidal-facet is usually absent 223 (1); astragalus (Transverse Diameter/Height) ratio = 1 <TD/H <1.2 252 (1); astragalus (Antero-Posterior Diameter/ Height) ratio = 0.65 253 (1); proximal border of the anterior side of the metacarpal III is straight 271 (0). The clade is weakly supported (Bremer index = 1). The species Hyrachyus eximius Leidy, 1871 is placed as the sister taxon of the Rhinocerotidae .