Doctoral Dissertation Improvement: Dental Microwear of Pliocene Bovids from East African Hominin Sites: Implications for Paleoenvironmental Dynamics and Human Evolution

许多研究人员认为，上新世气候变化是人类进化的动力。其基本思想是，向更干燥、更开放环境的转变导致了两足动物的适应和对稀树草原资源（包括大型食草哺乳动物）的消耗。然而，最近的古环境重建表明，上新世人类占据了更多变化或镶嵌的栖息地，包括开放和封闭的环境。虽然许多技术已被用来完善我们对东非古环境的理解，但这些技术并没有导致重建共识。该项目将通过引入一个新的独立数据集来推断实际个体在死亡前几天的饮食和栖息地，从而测试与南方古猿和阿法种相关的四个地点的古环境的竞争假设。本研究使用牙齿微磨损纹理分析来重建来自 Kanapoi（8 属）、Allia Bay（7 属）、Laetoli（8 属）和 Hadar（9 属）化石牛科动物的饮食中吃草的比率，从而重建生态环境。该项目将重建这四个重要的早期古人类遗址的古环境，以及生态环境如何随着居住在那里的古人类的时间跨度而发生变化。 智力优点：将生成现存牛科动物和化石牛科动物的微磨损纹理的大型数据库，并将为未来的研究提供大量的比较集合。它还将作为分类均变论的一个重要测试，在使用动物群组合作为古环境代理时经常假设分类均变论。此外，由于南南古猿和阿法南古猿的进化变化被广泛认为是对古生境变化的适应，因此这项研究改进的重建将对理解上新世东非环境变化与人类进化之间的关系具有重要意义。 这项研究的更广泛影响包括为来自服务不足的 EPSCoR 州的女研究生建立一个博士论文研究项目，并通过阿肯色大学荣誉学院学生环境动力学研究指导体验 (HERMES) 项目为本科生提供研究助理奖学金。它将为学生提供数据收集技术和研究方法的培训。

Many researchers have suggested that Pliocene climate change was a motive force for human evolution. The basic idea was that a shift toward drier, more open settings led to adaptations for bipedality and the consumption of savanna resources, including large grazing mammals. However, more recent paleoenvironmental reconstructions suggest that Pliocene hominins occupied more variable or mosaic habitats including both open and closed settings. While many techniques have been used to refine our understanding of the paleoenvironments of eastern Africa, these have not led to consensus reconstructions. This project will test competing hypotheses for the paleoenvironments of four sites associated with Australopithecus anamensis and A. afarensis by bringing a new, independent dataset for the inference of diet and by extension, habitats, of actual individuals in the days preceding their death. This study uses dental microwear texture analysis to reconstruct ratios of graze to browse in the diet, and therefore ecological contexts, of fossil bovids from Kanapoi (8 genera), Allia Bay (7 genera), Laetoli (8 genera) and Hadar (9 genera). This project will reconstruct the paleoenvironments of these four important early hominin sites and how ecological settings may have changed over the temporal spans of the hominins that lived there. Intellectual Merit: A large database of microwear textures for both extant and fossil bovids will be generated, and will provide a substantial comparative collection for future research. It will also serve as an important test of taxonomic uniformitarianism, which is often assumed in the use of faunal assemblages as paleoenvironmental proxies. In addition, since evolutionary changes in A. anamensis and A. afarensis are widely considered to be adaptations to shifting paleohabitats, the improved reconstructions resulting from this study will have important implications for understanding the relationship between environmental change and human evolution in eastern Africa during the Pliocene. The broader impacts of this study include establishing a doctoral dissertation research program for a female graduate student from an underserved, EPSCoR state and provide a research assistantship to an undergraduate through the University of Arkansas Honors College-Environmental Dynamics Research Mentoring Experience for Students (HERMES) program. It will provide both students with training in data collection techniques and research methods.