Dissertation Research: The Phylogenetic Position of Otavipithecus Namibiensis Quantitative Character Coding in Hominoid Phylogeny Reconstruction

该项目将分析纳米比亚新近发现的中新世古人类Otavipithecus namibiensis的进化关系。中新世类人猿是一种多样化的类人猿化石组合，在距今大约2200万年到500万年前占领了旧世界，它既产生了人类，也产生了我们最接近的亲属--非洲类人猿。因此，了解这些早期类人猿的进化关系对研究人类起源至关重要。这项研究还将解决类人族研究中的一个具体方法问题：定量形态特征在重建类人族进化关系中的作用。目前将数量特征编码为离散特征状态的方法用于分支分析，以及几种灵长类系统学新的基于统计学的方法将被应用于从类人猿下颌骨获得的形态测量数据。将对这些方法的相对有效性进行比较。研究样本将包括美国、欧洲和非洲收藏的化石和现存的类人下颌骨，重点是构建有效的生物样本和最大化样本大小。进化分析将使用当前计算机辅助的系统发育重建方法进行，并将根据这些结果检验先前所述的关于南美田鼠进化关系的假说。除了对Otavipithecus进化亲缘关系的详细研究外，这项研究还将首次严格检验数量特征编码在灵长类动物系统发育重建中的作用，其结果最终可能推广到人科动物的其他解剖区域，以及对其他灵长类动物的研究。

This project will analyze the evolutionary relationships of Otavipithecus namibiensis, the recently discovered Miocene hominoid species from Namibia. The Miocene hominoids, a diverse assemblage of fossil apes which occupied the Old World from roughly 22 to 5 million years before present, gave rise both to humans and our closest living relatives, the African apes. Consequently, understanding the evolutionary relationships of these early apes is crucial to the study of human origins. This study also will address a specific methodological problem in hominoid studies: the role of quantitative morphological characters in the reconstruction of hominoid evolutionary relationships. Current methods of coding quantitative characters into discrete character states for cladistic analysis and several statistically-based methods new to primate systematics will be applied to morphometric data taken from hominoid mandibles. The relative effectiveness of these methods will be compared. The study sample will comprise fossil and extant hominoid mandibles housed in collections in the U.S., Europe, and Africa, with an emphasis on constructing valid biological samples and maximizing sample sizes. Evolutionary analysis will be performed using current computer-assisted methods of phylogeny reconstruction, and previously stated hypotheses concerning the evolutionary relationships of Otavipithecus namibiensis will be examined in the light of these results. In addition to being a detailed investigation of the evolutionary affinities of Otavipithecus, this study will provide the first rigorous examination of the role of quantitative character coding in primate phylogeny reconstruction, the results of which ultimately may be generalized to additional anatomical regions in hominoids, as well as to studies of other primate groups.