Tylocephalonyx, a new genus of North American dome-skulled chalicotheres (Mammalia, Perissodactyla). Bulletin of the AMNH ; v. 164, article 1

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New York : American Museum of Natural History
"Tylocephalonyx, new genus, which includes a single species, T. skinneri, is known from a quantity of material, including skulls and nearly complete postcranials from the Sheep Creek Formation (Nebraska) and the Split Rock vertebrate fauna (Wyoming). The most impressive morphological feature of T. skinneri is its domed skull; but dental, pedal, and other characters are also improtant in defining the species and determining its affinities and habits. Additional material of Tylocephalonyx from Oregon, Montana, Utah, and Colorado closely resembles T. skinneri but is too incomplete for definite reference. The morphology of Tylocephalonyx is compared with that of the well-known chalicothere species Moropus elatus, but similarities to Moropus matthewi, Moropus merriami, and Ancylotherium (Ancylotherium) pentelicum, are also noted. Tylocephalonyx belongs to the chalicotheriid subfamily Schizotheriinae and shows special affinities to the genera Moropus, Phyllotillon, and Ancylotherium. A discussionn of further relationships is inconclusive; Tylocephalonyx may have originated from near the common stem of Moropus, Phyllotillon, and Ancylotherium. Floral/faunal associations suggest that Tylocephalonyx lived in moist temperate forests of northwestern North America but also had a significant distribution onto the Great Plains, perhaps associated with riparian communities. Its range appears to have differed from that of contemporary Moropus, which is rarely or never found in the same deposits and is found in more open woodland associations. The morphology of Tylocephalonyx is consistent with browsing habits and possibly for rearing up on the hindlimbs during feeding as was proposed for other schizotheriines by Borissiak (1945) and Schaub (1943). Many aspects of the habits of Tylocephalonyx, however, are still obscure"--P. 5.
64 p. : ill., map ; 26 cm.
Includes bibliographical references (p. 62-64).