Doctoral Dissertation Research: Molar topographic shape as a system for inferring paleoecology and developmental patterning in cercopithecoid evolution

灵长类动物用臼齿来分解食物，这是消化和获取营养的第一步。正如预期的那样，臼齿的形状与物种消耗的食物类型密切相关。此外，已经发现臼齿的形状在胚胎中通过一种优雅的图案化机制产生，由此第一臼齿发育对后期发育的牙齿具有级联效应。由于牙齿是耐用的，并且在大多数化石组合中占主导地位，臼齿是一个很好的模型系统，可以用来阐明灭绝动物的生物学。该项目由博士生Julia Winchester（纽约州立大学斯托尼布鲁克大学）在Frederick Grine博士的指导下进行，检查了现存和灭绝的旧世界猴子的臼齿形状，以更好地了解它们的进化饮食适应，以及这些物种的胚胎发育模式。旧大陆的猴子表现出所谓的双齿型臼齿尖组织，关于可能为双齿型进化提供选择力的饮食类型的问题仍然存在。它是对主要由叶子或耐用的坚果、种子和/或水果组成的饮食的适应吗？此外，对早期牙齿发育的了解很少，即使是生活在旧世界的猴子。这项研究将使用X射线显微断层扫描等技术来创建活的和化石灵长类动物臼齿的虚拟模型，计算机科学的尖端分析技术将量化整个臼齿形状。对于已知饮食的活物种，将建立比较数据集，并用于推断灭绝物种的饮食进化转变。物种中个体内臼齿的相对形状和形式将与啮齿动物的实验研究进行比较，以得出关于猴子牙齿发育模式的第一个结论。通过这些方法，臼齿的使用作为一把钥匙来解开有关生活和化石灵长类动物的饮食适应和胚胎发育的问题，将有助于理解胚胎牙齿发育可能与适应功能有关的方式，以及进化适应如何受到现有发育机制的限制。在其更广泛的影响，该项目将（1）通过培训一名理科女毕业生，扩大代表性不足群体的参与，（2）通过开发免费软件和参与开放的、在线访问的牙齿形状数据库，加强研究基础设施，以及（3）通过公众宣传支持科学传播，以提高科学认识。

Primates use their molar teeth to break down food as a first step to its digestion and the acquisition of its nutrients. As might be expected, molar shapes are observed to be tightly linked to the types of foods a species consumes. Additionally, it has been found that the shapes of molar teeth are produced in embryo by an elegant patterning mechanism whereby first molar development has a cascade effect over later-developing teeth. Because teeth are durable and dominate most fossil assemblages, molars are an excellent model system by which to elucidate the biology of extinct animals. This project, conducted by doctoral student Julia Winchester (SUNY Stony Brook University) under the guidance of Dr. Frederick Grine, examines molar shape in living and extinct old world monkeys in order to better understand their evolutionary dietary adaptations, and the embryological developmental patterning of these species. Old world monkeys exhibit what is referred to as a bilophodont form of molar cusp organization, and questions persist regarding the type of dietary items that might provided the selective force for the evolution of bilophodonty. Is it an adaptation to diets that consisted largely of leaves or durable nuts, seeds, and/or fruits? In addition, very little is known regarding early dental development, even of living old world monkeys. This research will use technologies such as X-ray microtomography to create virtual models of molars of living and fossil primates, and cutting-edge analytical techniques from computer science will quantify whole tooth molar shape. For living species with known diets, comparative datasets will be built and used to infer dietary evolutionary transitions in extinct species. Relative shape and form across intra-individual molar teeth in species will be compared with experimental studies of rodents in order to make the first conclusions regarding dental developmental patterning in monkeys. Through these methods, the use of molar teeth as a key to unlock questions regarding dietary adaptations and embryological development in living and fossil primates will be developed, supporting understanding of the ways in which embryological dental development may be related to adaptive function, and how evolutionary adaptation is constrained by available developmental mechanisms.In its broader impacts, this project will (1) broaden participation of under-represented groups by training a graduate woman in science, (2) enhance the infrastructure for research via free software development and participation in open, online-accessible databases of dental shape data, and (3) support scientific dissemination through public outreach to enhance scientific understanding.