Collaborative Research: Tooth Wear and Diet Among Living and Fossil Primates

脸颊牙齿的不同形状大致反映了现存灵长类动物及其化石亲戚的饮食习惯。然而，牙齿与其他生物结构的不同之处在于，它们没有自我改造或修复的能力，而是必须继续发挥咀嚼功能，即使它们磨损了。这一问题在灵长类等长寿动物身上更为严重。这个项目研究了牙齿磨损如何影响两种灵长类动物的食物分解功能，这两种灵长类动物的牙齿类人猿和旧大陆猴之间的差异很大，并探讨了这些模式揭示了它们之间的饮食进化和竞争。这项工作的数据将通过对博物馆标本的微ct扫描收集，并通过一个基于网络的存储库向研究人员、教育工作者和公众开放，从而改善获取和教育机会，特别是在检查稀有化石方面。这项研究将通过为科学界开发新的、可免费获得的软件来加强现有的方法，并通过专门讨论这一主题的会议促进科学交流。本科生将接受适用于广泛STEM专业的科学流程和方法的培训。项目的发现将通过展览向公众传播，让普通观众在杜克狐猴中心与研究人员和灵长类动物化石标本直接互动，并通过为青少年暑期科学营开发教育材料。该项目解决了在科学理解颊齿形状如何随着牙齿磨损和随之而来的功能影响而变化的重大差距。尽管人们普遍认为自然选择在灵长类动物的整个繁殖过程中继续作用于它们的牙齿，即使是在牙齿磨损的过程中，但大多数灵长类动物的摄食生态学研究都集中在牙齿的原始形态上。这一焦点来自于方法依赖于使用牙冠的可识别和同源特征，这些特征通常被磨损高度修改或抹掉，使磨损的牙齿无法提供信息。无同源性的咬合表面几何量化的发展，被称为牙齿地形度量，使研究人员能够扩展跨磨损系列的比较，并更好地表征终身牙齿形式-功能关联。本研究利用这些技术来解决猿和旧大陆猴（所谓的翼突猴）磨牙的不同结构模式如何随着牙齿磨损而变化，以维持和/或增强与咀嚼效率和耐磨性相关的特征。具有不同饮食和饲养基质偏好的活物种将用于系统发育信息比较，包括牙齿地形，牙釉质厚度分布和牙齿磨损。这一广泛的比较样本将为研究3500万至1500万年前的化石类人猿的牙齿磨损奠定基础，以了解化石分类群的饮食生态，并评估猴子的翼突磨牙与现存猿类中仍观察到的原始尖齿模式的适应意义。这项工作的结果将描述翼突龙牙齿的终身功能有效性，并告知在过去1500万年中观察到的旧大陆猴子辐射与猿相比的成功。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The diverse shapes of cheek teeth are broadly reflective of the diets that living primates and their fossil relatives consumed. Yet teeth stand apart from other biological structures in that they do not have the capacity to remodel or repair themselves and instead must continue to perform their chewing function, even as they wear down. This is an issue exacerbated in long-lived animals such as primates. This project investigates how tooth wear affects food break-down functionality in two primate taxonomic groups with highly contrasting teeth—apes and Old World monkeys—and explores what these patterns reveal about the dietary evolution and competition between them. Data for this work will be collected via microCT scanning of museum specimens and made accessible via a web-based repository open to researchers, educators, and the general public, improving access and educational opportunity, particularly for examining rare fossils. This research will enhance existing methodologies through development of new, freely available software for the scientific community and promote scientific communication with a conference session dedicated to this subject matter. Undergraduates will receive training in the scientific process and methods applicable to a wide range of STEM professions. Project findings will be publicly communicated through an exhibit that allows general audiences direct interaction with researchers and fossil primate specimens at the Duke Lemur Center, and through development of educational material for their youth summer science camps.This project addresses the significant gap in scientific understanding of how cheek tooth shape changes as teeth wear and the attendant functional implications. Despite general acknowledgement that natural selection continues to operate on primate dentitions throughout their reproductive lives, even as teeth wear, the majority of primate feeding ecology investigations have focused on the initial pristine form of teeth. This focus has emerged from the methodological dependence on using identifiable and homologous features of tooth crowns, which are often highly modified or obliterated by wear, rendering worn teeth uninformative. The development of homology-free quantifications of occlusal surface geometry, known as dental topographic metrics, liberates researchers to extend comparisons across wear series and better characterize lifetime dental form-function associations. This research leverages these techniques to address how the divergent structural patterns of ape and Old World monkey (so called bilophodont) molars change with tooth wear to maintain and/or enhance features related to chewing efficiency and wear resistance. Living species with diverse dietary and feeding substrate preferences will be used in phylogenetically-informed comparisons incorporating dental topography, enamel thickness distribution, and tooth wear. This broad comparative sample will form the basis for the study of dental wear among well-sampled fossil anthropoids from 35 to 15 million years ago to inform both the dietary ecology of fossil taxa and evaluate the adaptive significance of bilophodont molars of monkeys compared to the primitive cusp pattern still observed in living apes. The results of this work will describe the lifetime functional effectiveness of bilophodont teeth and inform the observed success of the Old World monkey radiation compared to that of apes over the past 15 million years.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.