DISSERTATION RESEARCH: The Evolution of Specialized Teeth and Jaws in Early Mesozoic Ray-Finned Fishes and Their Impact on Widespread Niche Differentiation

鳍鱼（如鳟鱼、小丑鱼、海马、鲈鱼）是当今地球上最多样化的脊椎动物群体，它们在体型、头骨和下巴形态以及牙齿特化方面表现出巨大的生理差异。鳐鱼有着悠久的进化历史，本研究的重点是生活在中生代早期（2.5亿- 1.9亿年前）的两种灭绝的鱼类：盘状的深身dapediids和鱼雷状的原始redfieldiids。这两组鱼类提供了一个理想的对比（例如，深的身体与窄的身体，颌骨的差异），用于测试牙齿和颌骨解剖和形态专门化影响的假设。研究人员将把这种体型与鱼类的饮食、栖息地偏好、行为和生态位专业化进行比较。该项目将研究中生代早期的化石，这是地球历史上一个不稳定的时期，全球构造事件改变了地球的地理位置，塑造了不同生态系统中生物的多样性。这项研究将增加我们对这两组灭绝鱼类如何适应占据不同生态空间和利用不同食物来源的理解。该研究将利用最先进的二维和三维数字成像技术，如微型计算机断层扫描（CT）扫描。这些工具将测量保存完好的红田古猿和速动古猿化石的下颌和颅骨解剖和形态以及牙齿微磨损。利用这些数据，该项目的研究人员将能够解决关于牙齿和颌骨形态如何与生态位空间和进化历史相关的假设。该项目将为研究生和本科生提供形态学和形态计量学技术方面的培训，从这项研究中获得的数据将被编录在在线数据库中。

The ray-finned fishes (e.g., trout, clownfish, seahorse, bass) are the most diverse group of vertebrates on Earth today and display a vast array of physical differences with regard to body shape, skull and jaw morphology, and tooth specializations. Ray-finned fishes have a long evolutionary history, and this study focuses on two extinct groups of fishes that lived during the Early Mesozoic (250-190 million years ago): the disc-shaped, deep-bodied dapediids and the torpedo-shaped, primitive redfieldiids. These two groups of fishes provide an ideal contrast (e.g., deep body versus narrow body, differences in jaws) for testing hypotheses of the impact of specialization of tooth and jaw anatomy and morphology. The researches will compare this body shape contrast with the diet, habitat preference, behavior, and niche specialization of the fish. The project will study fossils from the Early Mesozoic, a volatile time in Earth's history with global tectonic events changing the geography of the planet and shaping the diversity of organisms in different ecosystems. This research will increase our understanding of how these two groups of extinct fishes have adapted to occupy different ecological spaces and exploit different food sources. The research will utilize state-of-the-art two- and three-dimensional digital imaging techniques, such as micro-computed tomography (CT) scanning. These tools will measure jaw and cranial anatomy and morphology as well as tooth microwear, in well-preserved redfieldiid and dapediid fossils. Using these data the investigators of this project will be able to address hypotheses about how tooth and jaw morphology relate to ecological niche space and evolutionary history. This project will provide graduate and undergraduate training in morphological and morphometric techniques, and data obtained from this study will be catalogued in online data repositories.