Master's Theses

Date of Award

Summer 1992

Degree Name

Master of Science (MS)

Department

Geosciences

Advisor

Richard Zawerksi

Abstract

The teleoceratines were members of the last wave of rhino immigrants to North America, and together with the genus Aphelops, represent the last rhinos on the North American continent. Teleoceras was a hippo-like rhinoceros that existed from the early Barstovian to the late Hemphillian land-mammal age. Geographically, the genus roamed from Florida through the present day High Plains to the west coast of North America. The genus is characterized by grossly shortened limbs and a deep, concave body. The skull is brachycephalic with broad, flaring zygomatic arches and lambdoid crests. The nasals are fused with a small rugosity that indicates the presence of a small horn. The incisors are lost except for the blade-like I1/ and tusk-shaped I/2. The premolars are reduced with a loss of the P1/1 and occasional loss of the P/2. The molars are hypsodont with a complicated crown pattern on the upper teeth. Seven species of Teleoceras are presently recognized. Five species are normal in size and two are dwarf offshoots. Species can be identified by the crown pattern on the upper molars, size of certain cranial features, overall size of the skeleton, size of the limb elements, and number of carpal elements. Measurement of the tusks (I/2) and cranial features also aids in gender identification. Seven age groups of Teleoceras are determined on the basis of tooth eruption and wear on the metastyle. Hypsodonty and the presence of grass seeds in articulated skeletons confirm that Teleoceras was a grazer. There is a general trend toward an increase in size and robustness. The dwarf species show a decrease in size with a marked increase in robustness that surpasses the normal species.

Rights

Copyright 1992 George J. Gerhold

Comments

Notice: This material may be protected by copyright law (Title 17 U.S. Code).

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