Dental Analysis for Dietary Reconstruction

试图了解人类祖先饮食适应的古人类学家研究现代非人类灵长类动物，以确定牙齿结构和功能之间的联系。牙釉质是牙齿坚硬的外层覆盖物，是牙齿解剖学中最受关注的方面之一，因为它直接与食物相互作用。这项研究探索了牙釉质的厚度和结构是如何在很短的进化时间内发生变化的，这与灵长类动物的饮食和牙齿功能的特定方面有关。为了实现这一目标，这项研究利用了俄亥俄州立大学收藏的灵长类骨骼，其中包括来自不同野外地点的旧大陆猴子骨骼。与这些骨骼遗骸相关的饮食和牙齿使用数据为研究现存灵长类动物的釉质变化与其饮食和口腔加工行为的关键特征之间的关系提供了机会。作为这项工作的结果，将提供大量灵长类动物的显微CT扫描(~400颗牙齿)和组织切片(60-80颗牙齿)，从而加强研究和教育的基础设施。本科生参与和培训这一项目有助于STEM劳动力的发展。通过俄亥俄州立大学的人类学公共推广计划传播项目结果将增加公众对科学和技术的参与。最后，这项研究与当地的一个项目相关联，该项目对社区成员的环境、健康和教育有好处。这个项目填补了古人类学家对牙釉质如何随着饮食和口腔加工行为的特定方面而演变的理解的空白。目前，灵长类动物的厚牙釉质呈现出一个模糊的功能信号，表明它适应了硬的和/或研磨的饮食。这项研究调查了釉质厚度分布的各个方面，以及釉质棱镜与牙齿磨损表面形成的角度是否与硬物摄食(即吞噬)有关，这可能为推断化石物种对吞噬的适应提供了基础。对釉质厚度的进一步的古人类学解释是，厚重的釉质可能意味着适应习惯性的吞噬，或者只适应在没有较软食物的时期食用坚硬食物，这是一种所谓的“后备”喂养策略。这项工作更全面地评估了习惯性和后备硬性食物消费者的灵长类动物的牙釉质厚度，询问与这两种适应相关的牙釉质厚度分布和/或牙釉质棱柱方向是否存在差异。此外，研究属于不同进化谱系的物种厚釉中潜在的发育差异，阐明了釉质在较短进化时间跨度内进化能力的发育途径。最后，之前的研究表明，在食叶灵长类动物中，对稀薄牙釉质的选择限制了牙釉质的进化；这个项目使用了饮食差异很大的食叶灵长类动物样本，更全面地评估了这一观点。总之，对这些相关问题的研究阐明了选择压力对牙釉质总厚度、牙釉质厚度分布和牙釉质结构的影响，为深入了解这些特征的进化性和限制性提供了依据。反过来，这些洞察力将为从牙釉质中收集饮食适应的古人类学推断奠定更坚实的基础。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Paleoanthropologists who seek to understand dietary adaptations in human ancestors study modern non-human primates to identify links between dental structure and function. Enamel, the hard, outer covering of a tooth, is one of the most scrutinized aspects of dental anatomy because it interacts with food directly. This research explores how the thickness and structure of tooth enamel, which appear to change over short evolutionary time periods, relate to specific aspects of diet and tooth function in primates. To achieve this goal, this research leverages a collection of primate skeletons housed at The Ohio State University, consisting of Old World monkey skeletons from various field sites. Data on diet and tooth use associated with these skeletal remains provides opportunities to investigate how enamel variation in living primates relates to critical features of their diets and oral processing behavior. As a result of this work, a large collection of microCT scans (~ 400 teeth) and histological slides (60-80 teeth) of primates will be made available, thus enhancing infrastructure for both research and education. Involvement and training of undergraduates in this project contributes to the development of a STEM workforce. Communication of project findings via The Ohio State University's Anthropology Public Outreach Program will increase public engagement with science and technology. Finally, this research is associated with a local project, which has environmental, health, and educational benefits to community members.This project fills gaps in paleoanthropologists’ understanding of how enamel evolves in response to specific aspects of diet and oral processing behavior. Currently, thick enamel in primates presents an ambiguous functional signal, suggesting adaptation to hard and/or abrasive diets. This research investigates whether aspects of enamel thickness distribution, and the angles that enamel prisms make with tooth wear surfaces, are associated with hard-object feeding (i.e., durophagy), potentially providing a basis for inferring adaptation to durophagy in fossil species. Further confounding paleoanthropological interpretation of enamel thickness is that thick enamel may signify adaptation to either habitual durophagy or to the consumption of hard foods only during periods when softer foods are not available, a so-called “fallback” feeding strategy. This work more fully assesses enamel thickness in primates that are habitual vs. fallback hard-food consumers, asking whether there are differences in enamel thickness distribution and/or enamel prism orientation related to these two adaptations. Additionally, investigating potential developmental differences in the thick enamel of species that belong to different evolutionary lineages elucidates developmental pathways underlying enamel's ability to evolve over short evolutionary time spans. Finally, previous studies have suggested that in leaf-eating primates, selection for thin enamel constrains the evolution of enamel; this project more fully assesses this suggestion using a sample of leaf-eating primates with wide dietary variation. Altogether, research into these related questions elucidates selection pressures shaping overall enamel thickness, enamel thickness distribution, and enamel structure, providing insight into evolvability and constraint in these features. In turn, these insights will form a more robust foundation for paleoanthropological inference about dietary adaptation gleaned from tooth enamel.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.