Dissertation Reseach: Determinants of Form in the Pubis of Middle/Late Pleistocene Anatomically Modern Humans and Neandertals

尼安德特人骨盆的产道前部（上支，或SPR）与现代人类的SPR在三个方面不同：它更长，更薄，尼安德特人男性（而不是女性）拥有最长的SPR。根据尼安德特人和现代人骨骼差异的总体模式，这些差异与预期相反。关于尼安德特人SPR的形状，人们提出了许多假设，但缺乏检验这些假设所需的生物力学数据。这项研究将解决四个问题：1)根据对后来的原始人（尼安德特人+现代人）进行更全面的SPR采样，报告的形状差异模式是否成立？2) SPR在近代人类中有多大的变化？3)现有的关于SPR在后来的人科动物中变异的假设是否可以被拒绝或支持？4)躯干扭转假说是唯一能解释在SPR中观察到的所有后来原始人的形状差异的假说，它能被拒绝还是支持？最近的化石发现大大增加了后来原始人SPR的可用数量，而CT扫描仪的增加使得对SPR内部解剖结构的分析更加彻底。该项目将使用CT扫描仪收集测试SPR功能和变异假设所需的横截面数据。为了评估SPR变化的现代范围，几乎每一个前全新世（公元前8000年以上）欧亚晚期原始人的SPR都将被检查，同时也将检查大量不同的近代人类样本。SPR在分娩、运动、姿势以及腹部和大腿之间的肌肉力量传递中起作用。该项目将有助于阐明尼安德特人SPR的生物力学作用，以及尼安德特人和现代人之间SPR差异可能表明功能和行为差异的程度。

The front portion of the birth canal (the superior ramus, or SPR) of the Neandertal pelvis differs from the modern human SPR in three ways: it is much longer, it is much thinner, and Neandertal males (not females) possess the longest SPR. These differences run contrary to what is expected, based on overall patterns of bony differences between Neandertals and modern humans. Many hypotheses accounting for the shape of the Neandertal SPR have been offered, but the biomechanical data needed to test them have been lacking. Four questions will be addressed by this study: 1) do the reported patterns of shape differences hold true in light of a fuller sampling of SPR of later hominids [Neandertals + modern humans]? 2) how much does the SPR vary in recent humans? 3) can any of the existing hypotheses for SPR vari-ation in later hominids be rejected or supported? 4) can the trunk torsion hypothesis, the only hypothesis to address all of the observed shape differences seen in the SPR of later hominids, be rejected or supported? Recent fossil discoveries have greatly increased the available number of SPR of later hominids, while the increased availability of CT scanners allows a more thorough analysis of internal SPR anatomy. This project will use CT scanners to gather the cross-sectional data needed for testing hypotheses of SPR function and variation. Nearly every pre-Holocene (older than 8,000 BC) Eurasian later hominid SPR will be examined, as will a large and diverse sample of recent humans in order to assess the modern range of SPR variation. The SPR plays a role in childbirth, locomotion, posture, and muscular force transmission between ab-domen and thigh. This project will help clarify the biomechanical role of the SPR in Neandertals, as well as the extent to which SPR differences between Neandertals and modern humans may be indicative of functional and behavioral differences.