The teeth of primates, both living and fossil, represent the most complete evidence of the evolution, ecology, life history, and taxonomy of this important group. The microscopic structure of tooth enamel, a previously neglected aspect of tooth morphology, holds great promise for increasing our understanding of primate dental function and phylogenetic relationships. This research will document enamel variation in a broad taxonomic sample of living and fossil primates, and use these data to test specific functional hypotheses and to assess the phylogenetic utility of enamel characters. It represents an important step forward in the comprehensive study of these rare biological and fossil specimens. The research design consists of two components: 1) analysis of intraspecific and interspecific variation in enamel in a broad sample of living primates and 2) analysis of enamel evolution, based on comprehensive sampling of molar tooth enamel of fossil primates. Analyses will be based on scanning electron microscopy of histological specimens of mature enamel. The objectives of the study are: 1) To test the hypothesis that differences in occlusal enamel among functionally distinct areas of molar teeth are linked to differential resistance to wear. 2) To test the hypothesis of linkage between some enamel features and body size. 3) To test hypotheses of functional constraints on enamel structure among developmentally and functionally distinct parts of the dentition (e.g., incisors, canines, premolars, molars). 4) To explore the links between enamel structure and diet using comparative study of closely related primates that differ in diet, and statistical methods of matrix correlation analysis. 5) To assess the phyletic utility of enamel characters among living primates, and, using phylogenetically reliable enamel characters, to test hypotheses of relationships among fossil primates. This research will be the most comprehensive study of primate enamel structure to date. By study of mechanically important enamel characters it will contribute to a broader understanding of dental function and evolution in Primates. Moreover, it will go a long way towards establishing how enamel structure can and cannot be used to resolve questions of phylogeny and systematics.
