Collaborative Research: Paleoecology of Fossil Horses (Family Equidae) over the past 55 Million Years

合作研究：过去 5500 万年马科化石的古生态学

• 批准号: 9528020
• 负责人: Bruce MacFadden
• 金额: $ 8.66万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-03-01 至 2001-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9528020&HistoricalAwards=false
• 关键词: Collaborative; Research; Paleoecology; Fossil; Horses

MacFadden 9528020 The rich 55 million year fossil record of horses demonstrates evolution in dietary adaptation through time, potentially in response to environmental change. Tooth and skull morphology changed many times and are associated with adaptation to new diets. Using a combination of new methods, this research will test, for the first time, the prevailing theory that the earliest horses were browsers in rain forests and then gradually evolved into savanna grazers. Evolution from horse browsers to grazers is assumed to be an adaptive response to climatic changes and the associated changes in the distribution of vegetation types. During the Miocene (approximately 20 million years ago), North American savannas and grasslands spread and replaced rain forests as global climate became cooler, dryer and more seasonal. In this study, the diet of fossil horses will be compared to modern ungulate herbivores by examining: (1) the microscopic scratches made by vegetation on the surface of the teeth as viewed with an electron microscope; (2) restoration of chewing muscles; (3) analysis of size and shape of snouts; and (4) carbon isotopic composition in tooth enamel (the isotopic signature of savanna grasses is different than forest leaves and the specific isotopic signature of the diet should be incorporated in tooth enamel). The project thus uses four methods to study the same dietary questions and the detailed interaction of morphologic change with the environment. The results may significantly alter the classic story of horse evolution as it is currently presented in books and museum exhibits. Furthermore, they will provide detailed insights into the process of evolutionary change in mammals in response to changing climates and vegetation.

麦克法登9528020 的 丰富 5500万年化石记录 的 马在饮食适应方面表现出随时间的进化，可能是对环境变化的反应。 牙齿和头骨的形态改变了很多次，并与适应新的饮食有关。 使用新方法的组合，这项研究将首次测试最早的马是雨中浏览器的流行理论 森林，然后逐渐演变成草原食草动物。 从马浏览器到食草动物的进化被认为是对气候变化和相关的植被类型分布变化的适应性反应。 在中新世（约2000万年前），北美稀树草原和草原蔓延，并取代了热带雨林，因为全球气候变得更冷，更干燥，更季节性。 在这项研究中，化石马的饮食将与现代有蹄类食草动物进行比较，通过检查：（1）用电子显微镜观察牙齿表面植被造成的微观划痕;（2）咀嚼肌的恢复;（3）吻部的大小和形状分析;以及（4）碳同位素组成 在牙齿釉质中（热带草原草的同位素特征与森林树叶不同，食物的特定同位素特征应该包含在牙齿釉质中）。 因此，该项目使用四种方法来研究相同的饮食问题以及形态变化与环境的详细相互作用。 这些结果可能会显著改变马进化的经典故事，因为它目前出现在书籍和博物馆展品中。 此外，他们将提供详细的见解，以应对不断变化的气候和植被的哺乳动物的进化变化的过程。