Doctoral Research Improvement Grant: Systematics of Middle to Late Miocene Hominoidea

灵长类进化中最长期存在的问题之一是中中新世至晚中新世（1300 - 800万年）猿类之间、与现存的类人猿以及与人类之间关系的性质。科学家们对类人猿（猿）的关系提出了许多不同的假设，但不同方法的应用和不同骨骼特征的使用提出了一个问题：观察到的结果是否准确地代表了关系，或者它们是否只是所使用的方法和所选择的特征的人工制品。目前关于人类谱系早期代表的进化关系的假设主要依赖于对现存非洲猿和现代人类高度专业化特征的比较分析。这个项目将提供一个重要的新的角度对类人猿的关系，通过纳入更大范围的多样性和不太专业的形态在中新世的猿，以澄清的序列中的功能进化。这项研究涉及对来自17种现存灵长类动物的123种颅骨和颅后特征的综合分析，这些特征以前曾被用来推断中新世猿类之间的进化关系。这些性状将单独地、通过解剖系统和整体地与独立的（即，分子）进化关系的措施。Skeleton特征将首先通过线性测量进行量化，然后在排列测试中进行单独分析，以评估它们所包含的关于进化关系的信息的统计学意义。吝啬分析，然后将进行这些活的物种，以及四个晚中新世类人猿，使用这些功能，发现有最高的信息含量在解决关系。研究结果将显示不同方法和特征的选择在多大程度上影响了我们对中新世类人猿进化的看法，从而为阐明中新世猿和早期化石人类的进化关系提供更坚实的基础。本项目将为不同方法和骨骼特征在推断进化关系方面的效用提供新的见解，以及对目前关于中新世中期到晚期猿类进化关系的假设的严格检验。对中新世猿类的研究是至关重要的，因为它们代表了人类的近亲，而一些中新世晚期的物种很可能被证明是现代人类谱系的早期成员。因此，更好地了解中新世猿类特征进化的顺序，并澄清它们与现生猿类的关系，将对理解人类进化产生重大影响。

One of the most long-standing problems in primate evolution is the nature of the relationships of Middle to Late Miocene (13-8 million years old) apes to each other, to living great apes, and to humans. Scientists have formulated many different hypotheses about hominoid (ape) relationships, but the application of different methods and the use of different skeletal features have raised the question of whether the observed results are an accurate representation of relationships or whether they are simply an artifact of the methods used and traits chosen. Current hypotheses about the evolutionary relationships of early representatives of the human lineage rely largely on comparative analyses of the highly specialized features in living African apes and modern humans. This project will offer an important new perspective on hominoid relationships by incorporating the greater range of diversity and less specialized morphologies seen in Miocene apes in order to clarify the sequence in which features evolved. This research involves a comprehensive analysis of 123 cranial and postcranial features, from 17 living primates, which have been previously used to infer evolutionary relationships among Miocene apes. These traits will be compared individually, by anatomical system and holistically, to independent (i.e., molecular) measures of evolutionary relationships. Skeletal features will first be quantified by linear measurements, and then analyzed individually in permutation tests to assess the statistical significance of the information they contain about evolutionary relationships. Parsimony analyses will then be performed on these living species, as well as four later Miocene apes, using those features that are found to have the highest information content in resolving relationships. The results should indicate how much the choice of different methods and traits is influencing our perception of Miocene hominoid evolution, and thus provide a firmer foundation for clarifying the evolutionary relationships of both Miocene apes and early fossil humans.This project will provide new insights into the utility of different methods and skeletal traits for inferring evolutionary relationships, and a rigorous test of current hypotheses about evolutionary relationships in Middle to Late Miocene apes. The study of Miocene apes is critical because they represent close relatives of humans, and some later Miocene species are likely to prove to be early members of the lineage leading to modern humans. As a consequence, a better understanding of the sequence in which traits evolved in Miocene apes and clarification of their relationships to living apes will have major implications for understanding human evolution.