Doctoral Dissertation Research: Morphological Integration in the Hominid Cranial Base

这里提出的研究将评估原始人类颅底的功能形态，以及它在重建早期人类进化模式(即原始人类系统发育模式)中的作用。这项研究意义重大，因为它将批判性地检验一个解剖区域的功能和系统发育关系，该区域在本世纪的大部分时间里一直是争论的主题。在这样做的过程中，它将收集定量的姿势数据，这将极大地提高我们将灵长类位置行为与形态联系起来的能力。最后，它将提出一种方法，通过这种方法，功能和结构推断可以用于系统发育分析。也就是说，功能上或结构上相互关联的解剖特征将被分组为复合体，然后在分支分析(一种系统发育重建方法)中被视为一个单元(即，作为单个特征加权)。这种方法适用于生物学所有领域的分支分析，而不考虑正在研究的有机体或解剖区域。颅底是功能和系统发育研究的合适的解剖学焦点。从功能形态的角度来看，影响颅底形态的因素很多。这些因素包括大脑大小、姿势、发声、咀嚼和面部结构。因此，有许多功能假设可供测试。从系统发育的角度来看，颅骨的基本特征在围绕早期人类进化模式的争议中扮演着至关重要的角色。我们自己属的早期成员(例如能人、直立人)与一些南方古生物物种共享一些高级基本颅骨特征。这些特征要么表明这些物种与我们属的祖先成员之间存在密切的进化关系，要么表明高级基本颅骨特征在两个或更多早期人类谱系中独立进化。最后，从历史的角度来看，颅底很重要。长期以来，人们一直认为人类的颅底与其他灵长类动物的颅底是不同的。因此，一个基本的颅骨特征被用来识别第一个被发现的南方古猿头骨是人类祖先。

The research proposed here will evaluate the functional morphology of the hominid cranial base, and its role in reconstructing patterns of early human evolution (i.e., patterns of hominid phylogeny). This research is significant because it will critically examine the functional and phylogenetic relationships of an anatomical region that has been the subject of debate for most of this century. In the process of doing so, it will collect quantitative postural data that will vastly improve our ability to relate primate positional behavior and morphology. Finally, it will propose an approach whereby functional and structural inferences may be used in phylogenetic analysis. Namely, anatomical features that are functionally or stucturally related to each other will be grouped into complexes, and will then be treated as a unit (i.e., weighted as a single feature) in a cladistic analysis (a method of phylogeny reconstruction). This approach is relevant to cladistic analyses in all fields of biology, regardless of the organism or anatomical region that is under investigation. The cranial base is an appropriate anatomical focus for functional and phylogenetic research. From the standpoint of functional morphology, a wide range of factors may influence basicranial form. Such factors include brain size, posture, vocalization, mastication, and facial architecture. Consequently, there are many functional hypotheses available for testing. From a phylogenetic standpoint, basicranial traits play a vital role in the controversey surrounding patterns of early human evolution. Early members of our own genus (e.g., Homo habilis, Homo erectus) share a number of advanced basicranial features with some australopiothecine species. These features either indicate a close evolutionary relationship between these species and the ancestral members of our genus, or that advanced basicranial characters evolved independently in two or more lineages of early humans. Finally, the cranial base is important from an historical perspective. It has long been recognized that the cranial base of humans is distinct from that of other primates. As a result, a basicranial feature was among those used to identify the first recovered australopithecine skull as being a human ancestor.