Doctoral Dissertation Improvement: Morphological Integration and Evolution of the Hominoid Vertebral Column

现存的猿类在躯干和四肢上都有一些衍生的骨骼形态，这些特征使它们区别于许多其他灵长类和哺乳动物。传统上，这些形态中的许多都与使用直立躯干姿势有关。这种根本性的转变是否发生在所有猿类的共同祖先身上，或者它是否在多个谱系中独立进化，仍然存在争议。通过相同的遗传或发育途径进行独立进化，这是一种复杂且难以检测的现象。在理解猿类运动进化的过程中，平行性问题是一个深刻的问题，因为它是理解运动的主要变化何时发生以及哪些行为是人类两足行走的必要前兆的基础。这个问题在化石记录中也遇到了，某些化石混淆了对类人猿进化和直立躯干姿势进化次数的理解。脊柱在姿势和运动中起着核心作用，它的方向是哺乳动物身体规划的主要类型。本研究旨在测试假设的平行进化采用定量进化方法，以确定模式的整合和潜在的限制可进化的形态。这些方法将被用来解决长期存在的争议的次数，正形已经在生活和化石类人猿进化。这项研究的智力价值包括它对进化和发育生物学领域的模型和理论的综合贡献。这项工作是一个更大的研究项目的一部分，该项目旨在量化整个灵长类动物颅后骨骼的形态整合模式。这项工作的更广泛的影响，包括促进研究生的研究培训的一个学生，并在伊利诺伊大学以及其他学术机构的教师和研究生之间的合作。

The living apes share a number of derived skeletal morphologies of the trunk and limbs, features that distinguish them from many other primates and mammals in general. Traditionally, many of these morphologies have been associated with the use of upright trunk posture. Whether this fundamental shift occurred once in the common ancestor of all apes or whether it evolved independently in multiple lineages remains contentious. Parallelism, independent evolution through identical genetic or developmental pathways, is complicated and notoriously difficult to detect. The problem of parallelism in understanding locomotor evolution amongst apes is profound because it underlies the understanding of when major changes in locomotion occurred and which behaviors were the necessary precursors to human bipedalism. This problem is also encountered in the fossil record where certain fossils confound the understanding of hominoid evolution and the number of times that upright trunk posture has evolved. The vertebral column plays a central role in posture and locomotion and its orientation characterizes the main types of body plans among mammals. This study seeks to test the hypothesis of parallel evolution by employing quantitative evolutionary methods to identify patterns of integration and potential constraints on evolvable morphologies. These methods will be used to resolve longstanding controversies concerning the number of times that orthogrady has evolved in living and fossil hominoids. The intellectual merit of this study includes its contribution toward a synthesis of models and theories in the fields of evolutionary and developmental biology. This work is part of a larger research project that aims to quantify patterns of morphological integration in the entire primate postcranial skeleton. Broader impacts of this work include facilitation of graduate research training for one student, and collaboration among faculty and graduate students at the University of Illinois as well as at other academic institutions.