Prevalence and etiology of linear enamel hypoplasia in non-human primates

This dissertation aims to further our understanding of the prevalence patterns and etiology of non-human primate linear enamel hypoplasia (LEH). LEH is a developmental defect of tooth enamel resulting from physiological stress. LEH has received minimal attention in non-human primates.; The objectives of this research are: (1){A0}To characterize LEH variation across nonhuman primate taxa. with attention to prosimians, gibbons, and the great ape-monkey LEH dichotomy (great apes have higher LEH frequencies than monkeys); (2){A0}To explore how much variation in LEH patterns across taxa is correlated with crown height and the duration of crown formation; (3){A0}to document intertooth variation in LEH expression at generic and species levels; (4) To examine the relationship between defect formation and physiologically stressful life history conditions (irregular provisioning, low dominance rank, and life in captivity).; To meet these objectives, primates from the following collections were studied: The Museum of Comparative Zoology (Harvard University), the Caribbean Primate Research Center Museum (University of Puerto Rico), the Oregon Regional Primate Research Center Collection (University of Oregon), the Museum of Vertebrate Zoology (UC Berkeley), and the Los Angeles County Museum of Natural History. LEH was observed using standard methods (Goodman and Rose, 1990). The Caribbean Primate Research Center provided life history data.; The results follow. No LEH was observed in prosimians. A higher LEH incidence than previously reported was found in gibbons. Crown height variation was only weakly correlated with LEH variation across taxa; the duration of crown formation may be a better predictor. The great ape-monkey LEH dichotomy may result from great ape-monkey differences in experiences of stress in combination with differences in crown formation spans. Rhesus monkeys exhibit a unique intertooth LEH distribution: LEH is preferentially expressed on the lower P3s. Individuals whose teeth formed prior to regular provisioning on the island of Cayo Santiago had higher defect counts than those whose teeth formed subsequently (overall incidence did not differ significantly). Individuals belonging to middle-ranking matrilines had higher defect counts than members of low- or high-ranking matrilines (overall incidence did not differ significantly among the three groups). LEH expression was only weakly correlated with life in captivity.