SGER: Dietary Paleoecology of Early Cenozoic Ungulates of North America

SGER：北美早新生代有蹄类动物的饮食古生态学

• 批准号: 0824657
• 负责人: Matthew Mihlbachler
• 金额: $ 2.49万
• 依托单位: New York Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0824657&HistoricalAwards=false
• 关键词: SGER; Dietary; Paleoecology; Early; Cenozoic

Dietary Paleoecology of Early Cenozoic Ungulates of North AmericaMatthew MihlbachlerI propose the study the dental microwear of Paleogene ungulates of North America to test hypotheses relating the paleodietary ecology of mammals to dental morphology and climate change. The fossil record documents the repeated evolution of lophodont dentitions from more bunodont forms. This trend is thought to correspond to a dietary shift from frugivory to folivory necessitated by global cooling, increasing seasonality, and associated habitat changes. The dental microwear methodology will be used to predict the diets of extinct species, to reconstruct the ecological profiles of successive faunas, and to trace the early dietary histories of major ungulate lineages, including the modern orders Artiodactyla and Perissodactyla. The dental microwear methodology liberates dental morphology from the task of making paleodietary inferences, thus allowing us to examine paleoecological change independent of morphological change and to track paleodiets at finer temporal scales. Solounias is largely responsible for developing the methods that will be used, while Mihlbachler has taken a role in further developing many aspects of these methods. The first year will be spent compiling casts of teeth for use wear analysis, curation of the cast library, and collection and analysis of data. Data analysis and dissemination of results will be completed in year two. This project will address two basic hypotheses that we believe are critical to mammalian evolutionary dietary paleoecology: Hypothesis 1: The evolution of lophodonty among Paleogene ungulates and ungulate-like mammals corresponds to a widespread shift from frugivory/omnivory in the beginning of the Paleogene to predominantly folivory by the close of the Paleogene. If dental microwear contradicts or is only loosely associated with dental classifications, it is a strong signal that mammalian paleodietary ecology should be more carefully evaluated, drawing evidence not just from dental morphology, but from dental use wear data (such as microwear) and other morphologically independent methods such as stable isotopes.Hypothesis 2: Mammalian paleodietary responses to climate changes occurred on time scales that are much finer than that which is suggested by trends in dental macroevolution. The Bighorn and Clark?s Fork Basins document a critical time period near the Paleocene-Eocene boundary. This critical time interval documents a rapid increase in CO2, the appearance of many immigrant taxa, and dwarfing events among several lineages. The dense sampling of mammals with high stratigraphic resolution through this interval afford us a rare opportunity to study paleoecological change during a critical interval in mammalian evolution at a scale of temporal resolution in which greenhouse warming processes and many evolutionary processes (speciation, extinction) are known to operate. In addition to developing a better understanding of evolution-ecology-climate dynamics, other broad impacts of this proposal are to expose a number of undergraduates and medical students to the scientific process to facilitate further research along similar lines and to provide results for an NSF funded website that is currently under development at the AMNH. Students will be hired to assist with the dental cast collection resulting from this proposal, and the entire collection of casts on modern and Miocene mammals collected by Solonious from prior NSF grants. These casts will be cataloged and made available to those who wish to conduct similar research in mammalian paleoecology.

北美早新生代有蹄类动物的饮食古生态学Matthew Mihlbachler我提议研究北美古近纪有蹄类动物的牙齿微磨损，以检验哺乳动物的饮食古生态学与牙齿形态和气候变化相关的假设。化石记录证明了脊齿兽的齿系是从更多的丘齿兽进化而来的。这一趋势被认为是对应于全球变冷，季节性增加，以及相关的栖息地变化所必需的饮食从食果性到食叶性的转变。 牙齿微磨损方法将用于预测灭绝物种的饮食，重建连续动物群的生态概况，并追溯主要有蹄类动物谱系的早期饮食历史，包括现代的偶蹄目和奇蹄目。牙齿微磨损的方法解放牙齿形态的任务，使古饮食推断，从而使我们能够检查古生态变化独立的形态变化和跟踪古饮食在更精细的时间尺度。Solounias主要负责开发将要使用的方法，而Mihlbachler则在进一步开发这些方法的许多方面发挥了作用。第一年将用于编制牙齿模型，用于磨损分析，管理模型库，以及收集和分析数据。数据分析和结果的传播将在第二年完成。本项目将解决两个基本假设，我们认为是至关重要的哺乳动物进化饮食古生态学：假设1：在古近纪有蹄类和有蹄类哺乳动物之间的lophodonty的演变对应于广泛的转变，从古近纪开始的食果/杂食为主的古近纪结束的食叶。如果牙齿微磨损与牙齿分类相矛盾或仅与牙齿分类松散相关，则这是一个强烈的信号，即应该更仔细地评估哺乳动物的古饮食生态学，不仅从牙齿形态学，而且从牙齿使用磨损数据中获取证据（如微磨损）和其他形态独立的方法，如稳定同位素。假设2：哺乳动物古饮食对气候变化的反应发生在时间尺度上，比牙齿宏观进化趋势所建议的要精细得多。大角和克拉克？的叉盆地文件的古新世-始新世边界附近的一个关键时期。这一关键的时间间隔记录了二氧化碳的迅速增加，许多移民类群的出现，以及几个谱系之间的矮化事件。通过这一间隔的哺乳动物与高地层分辨率的密集采样为我们提供了一个难得的机会，研究古生态变化的关键间隔哺乳动物进化的时间分辨率的规模，其中温室效应变暖过程和许多进化过程（物种形成，灭绝）是已知的操作。 除了发展一个更好地了解进化生态气候动力学，其他广泛的影响，这一建议是暴露了一些本科生和医学生的科学过程，以促进进一步的研究沿着类似的路线，并提供一个NSF资助的网站，目前正在开发中的AMNH的结果。学生将被雇用，以协助从这个建议产生的牙铸件收集，并在现代和中新世哺乳动物的铸件由Solonious从以前的NSF赠款收集的整个集合。这些模型将被编目，并提供给那些希望在哺乳动物古生态学方面进行类似研究的人。