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磨牙来分解食物，这是消化食物和获取营养的第一步。正如可能预期的那样，观察到磨牙的形状与一个物种消费的食物类型密切相关。此外，人们还发现，磨牙的形状是在胚胎中通过一种优雅的模式机制产生的，通过这种机制，第一颗磨牙的发育对后来发育的牙齿具有级联效应。由于牙齿是耐用的，并在大多数化石组合中占据主导地位，因此臼齿是解释灭绝动物生物学的极佳模型系统。该项目由纽约州立大学石溪分校的博士生Julia Winchester在Frederick Grine博士的指导下进行，研究了现存和灭绝的旧大陆猴子的磨牙形状，以更好地了解它们在进化中的饮食适应，以及这些物种的胚胎发育模式。东半球的猴子表现出一种被称为双齿形的磨牙尖组织，关于哪种饮食项目可能为双齿动物的进化提供选择性力量的问题一直存在。这是对主要由叶子或耐用坚果、种子和/或水果组成的饮食的适应吗？此外，人们对早期牙齿发育知之甚少，即使是现存的旧大陆猴子也是如此。这项研究将使用X射线显微断层成像等技术来创建活的和化石的灵长类动物的磨牙的虚拟模型，计算机科学的尖端分析技术将量化整个牙齿的磨牙形状。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。为了得出关于猴子牙齿发育模式的第一个结论，我们将把物种中个体内磨牙的相对形状和形式与啮齿动物的实验研究进行比较。通过这些方法，将开发利用磨牙作为解锁关于活的和化石灵长类动物的饮食适应和胚胎发育的问题的钥匙，支持对胚胎牙齿发育可能与适应功能相关的方式的理解，以及进化适应如何受到现有发育机制的限制。在其更广泛的影响中，该项目将(1)通过培训一名科学研究生来扩大未被充分代表的群体的参与，(2)通过自由软件开发和参与开放的、在线可访问的牙齿形状数据数据库来加强研究的基础设施，以及(3)通过公共宣传支持科学传播，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.