The Evolution of Primate Enamel Microstructure

灵长类动物的牙齿，包括活的和化石的，代表了这一重要群体的进化、生态学、生活史和分类学的最完整的证据。牙釉质的微观结构是以前被忽视的牙齿形态的一个方面，它为增进我们对灵长类牙齿功能和系统发育关系的理解带来了巨大的希望。这项研究将记录现存和化石灵长类动物的广泛分类样本中的釉质变异，并使用这些数据来检验特定的功能假说，并评估釉质特征的系统发育实用价值。这标志着对这些稀有生物和化石标本的全面研究向前迈出了重要的一步。研究设计由两部分组成：1)分析现存灵长类动物的广泛样本中牙釉质的种内和种间变异；2)基于对灵长类化石的磨牙牙釉质的全面采样，分析牙釉质的进化。分析将基于成熟牙釉质的组织标本的扫描电子显微镜。这项研究的目的是：1)检验磨牙不同功能区域咬合牙釉质的差异与不同的耐磨性有关的假设。2)检验釉质某些特征与体型的关联假设。3)检验牙列发育和功能不同部分(如门牙、尖牙、前磨牙、磨牙)之间对釉质结构的功能限制假说。4)通过对食性不同的近缘灵长类的比较研究，以及矩阵相关分析的统计方法，探讨釉质结构与饮食之间的关系。5)评估釉质性状在现存灵长类动物中的系统学效用，并利用系统发育可靠的釉质性状检验灵长类化石之间关系的假说。这项研究将是迄今为止对灵长类釉质结构最全面的研究。通过对牙釉质力学特性的研究，将有助于更广泛地了解灵长类动物的牙齿功能和进化。此外，它将在很大程度上有助于确定釉质结构如何能够和不能用于解决系统发育和系统学问题。

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.