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

灵长类动物用它们的臼齿来分解食物，作为消化和获取营养的第一步。正如所料，臼齿的形状被观察到与一个物种所食用的食物类型密切相关。此外，已经发现臼齿的形状是在胚胎中通过一种优雅的模式机制产生的，即第一臼齿的发育对后来发育的牙齿具有级联效应。由于牙齿坚固耐用，并且在大多数化石组合中占主导地位，磨牙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（纽约州立大学石溪分校）在Frederick Grine博士的指导下进行，研究现存和已灭绝的旧大陆猴子的臼齿形状，以便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一种被称为尖齿兽的臼齿组织形式，关于饮食类型可能为尖齿兽的进化提供了选择性力量的问题仍然存在。它是对主要由树叶或耐久的坚果、种子和/或水果组成的饮食的适应吗？此外，我们对早期牙齿的发育知之甚少，甚至对现存的旧大陆猴子也是如此。这项研究将使用x射线微断层扫描等技术来创建活体和化石灵长类动物臼齿的虚拟模型，并使用计算机科学的尖端分析技术来量化整个牙齿的臼齿形状。对于已知饮食的现存物种，将建立比较数据集，并用于推断灭绝物种的饮食进化转变。为了得出关于猴子牙齿发育模式的初步结论，将物种内臼齿的相对形状和形态与啮齿类动物的实验研究进行比较。通过这些方法，磨牙作为解开现存和化石灵长类动物饮食适应和胚胎发育问题的关键将得到发展，支持理解胚胎牙齿发育可能与适应功能相关的方式，以及进化适应如何受到现有发育机制的限制。就其更广泛的影响而言，该项目将(1)通过培训女研究生来扩大代表性不足的群体的参与，(2)通过免费软件开发和参与开放的、可在线访问的牙齿形状数据数据库来增强研究基础设施，以及(3)通过公众宣传来支持科学传播，以增强科学理解。

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.