2004 Denver Annual Meeting (November 7–10, 2004)

Paper No. 10
Presentation Time: 10:30 AM


BIASATTI, Dana M., Department of Geological Sciences, Florida State Univ and National High Magnetic Field Lab, 108 Carraway Building, Tallahassee, FL 32306-4100, WANG, Yang, Department of Geological Sciences, Florida State Univ and National High Magnetic Field Lab, 108 Carraway Bldg, Tallahassee, FL 32306-4100 and DENG, Tao, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, P.O. Box 643, Beijing, 10004, China, biasatti@mail.magnet.fsu.edu

Cenozoic localities in the Linxia Basin have yielded an abundance of well-preserved rhino fossils, ranging in age from 30 to 2.5 Ma and include individuals from 12 genera within the families Hyracodontidae and Rhinocerotidae. Stable carbon and oxygen isotopic compositions were determined for 49 individuals of these genera in order to examine paleodiet and ecology. First, three general conclusions were made regarding paleodiet and environmental change: 1) The d13C values of tooth enamel from all individuals indicate a primary diet of C3 browse and/or C3 grasses; 2) The carbon isotope compositions of all rhinos suggests that the Linxia Basin was a savannah or a mixed woodland/C3 grassland biome from the E. Oligocene to the L. Pliocene; and 3) The d18O values of the rhino tooth enamel for all individuals suggest that the climate in the area had not been stable from 30 to 2.5 Ma. Secondly, three more specific conclusions were drawn from this study: 1) d13C values suggest a generalized feeding habitfor Alicornops, whereas Parelasmotherium was found to have a more specialized diet. This was expected, given that Parelasmotherium had the most specialized dentition of all perissodactyls. Chilotherium was found to be a specialist at two time intervals, and a mixed feeder at three time intervals; 2) Allacerops and Indricotherium coexisted at 30 Ma and their average tooth enamel d13C and d18O values suggest that Indricotherium was more restricted to a closed habitat. Because Indricotherium was very large, it probably required a shaded or wet habitat to keep its body cooled; and 3) Chilotherium and Dicerorhinus coexisted at 6 Ma and isotopic analyses suggest that Chilotherium and Dicerorhinus shared similar feeding habits. Dicerorhinus dentition suggests it was a browser, and although Chilotherium had adaptations for grazing, it has been suggested that Chilotherium was not a true grazer. Isotopic results suggest that Chilotherium was a browser.