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，上新世的气候变化是人类进化的动力。基本观点是，向更干燥、更开放的环境的转变导致了对两足动物的适应和对稀树草原资源的消耗，包括大型食草哺乳动物。然而，最近的古环境重建表明，上新世人类占据了更多的可变或马赛克栖息地，包括开放和封闭的环境。虽然许多技术已经被用来完善我们对东非古环境的理解，但这些都没有导致共识的重建。该项目将测试与南方古猿和阿法南猿有关的四个遗址的古环境的相互竞争的假设，通过带来一个新的、独立的数据集来推断饮食，进而扩展到他们死亡前几天的实际个体的栖息地。本研究利用牙齿微磨损纹理分析重建了卡纳波伊（8属）、阿利亚湾（7属）、莱托利（8属）和哈达尔（9属）化石牛科动物的日粮中食草动物的比例，从而重建了生态环境。该项目将重建这四个重要的早期人类遗址的古环境，以及生态环境在人类生活的时间跨度内可能发生的变化。知识价值：将产生一个大型的现存和化石牛科动物微磨损纹理数据库，并将为未来的研究提供大量的比较收集。它还将作为分类均变论的重要检验，这种均变论通常被认为是使用动物组合作为古环境代用物。此外，由于南方古猿anamensis和南方古猿afarensis的进化变化被广泛认为是对古栖息地变化的适应，因此本研究的改进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。本研究的更广泛影响包括为来自服务不足的EPSCoR州的女研究生建立博士论文研究计划，并通过阿肯色大学荣誉学院-学生环境动力学研究指导经验（HERMES）计划为本科生提供研究助理奖学金。它将为两名学生提供数据收集技术和研究方法方面的培训。

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.