Hyrachyus, Chasmotherium, and the early evolution of helaletid tapiroids. American Museum novitates ; no. 2313

23 p. : ill. ; 24 cm.Includes bibliographical references (p. 23)."The rhinocerotoid family Hyrachyidae, which in its last review (Wood, 1934) included four genera and 12 species, is reduced to a subfamily, with one genus and three species, and included in the tapiroid family Helaletidae. Because the European genus Chasmotherium can be traced back to Hyrachyus (via the lineage Hyrachyus modestus (=H. 'stehlini')-Hyrachyus minimus-Chasmotherium cartieri), the monotypic subfamily Chasmotheriinae is transferred to the Helaletidae"--P. 19 & 21