Trabecular Bone Morphology and Locomotion in Extant Primates and Fossil Hominins

该项目开发了一种新的方法来重建化石中的步态和其他行为方面，并扩展了我们对解剖关节结构和功能之间关系的理解。 关于早期化石人类步态的两个主要争论是：（1）他们两足直立行走步态的性质（无论是现代人类的步态还是弯曲臀部和膝盖的步态），以及（2）在树上攀爬和移动是否仍然是这些早期物种生态行为的重要组成部分。 在过去的十年里，许多研究人员已经承认，这些争论已经陷入僵局，解决方案将需要关于生命期间功能活动的化石证据的新数据。 成像和分析的进步现在允许研究人员捕获和量化骨小梁的三维（3D）结构-对负荷历史最敏感的骨组织-在化石中，并提供生命期间关节负荷的证据，以超越这一僵局。本研究的主要目的是研究三维骨小梁结构与高等灵长类掌骨（手）和股骨（髋关节和膝关节）关节功能之间的关系。 更具体地说，本研究旨在（1）建立现代高等灵长类动物中骨小梁结构和习惯性关节姿势之间的关系，这些灵长类动物的步态方式不同（例如，涉及更多的弯曲或伸展关节），（2）检查关节的骨小梁特征与骨干的横截面强度之间的关系。 建立习惯性关节功能和关节内骨小梁结构之间关系的本质将使研究人员能够更准确地重建化石物种的步态。 这个项目将把它的发现应用于一个关于化石中功能行为的假设，即尼安德特人是否以不同于现代人类的方式使用他们的手。 这项研究需要最全面的分析，以日期的高等灵长类动物骨小梁结构。这项研究也有几个重要的更广泛的影响。 在这项研究中获得的扫描结果将公开提供，以促进更多的研究。 至少有一名博士生将从该项目中获得培训。 这将有助于开发一种新的行为重建方法，这将引起人类学以外的古生物学家的兴趣。 最后，该提案将促进地质学家和两名物理人类学家之间的跨学科研究，以及美国和日本研究人员之间的国际合作。

This project develops a new approach to reconstructing gait and other aspects of behavior in fossils, and expands our understanding of the relationship between anatomical joint structure and function. The two main debates concerning gait in early fossil humans are over (1) the nature of their bipedal, upright walking gait (whether it was modern human-like or a gait with bent hips and knees), and (2) whether or not climbing and moving in trees remained an important part of the ecological behavior of these early species. Over the last decade, many researchers have acknowledged that these debates have reached an impasse, and that a resolution will require new kinds of data regarding fossil evidence of functional activity during life. Advances in imaging and analysis now permit researchers to capture and quantify the three dimensional (3D) structure of trabecular bone - the bone tissue most sensitive to loading history - in fossils and provide the kinds of evidence of joint loading during life needed to move beyond this impasse. The primary goals of this research are to examine the relationships between 3D trabecular structure and metacarpal (hand) and femoral (hip and knee) joint functions in higher primates. More specifically, this research aims to (1) establish the relationships between trabecular bone architecture and habitual joint posture in modern higher primates that differ in their manner of gait (e.g., involving more flexed or extended joints), (2) examine the relationships between trabecular bone characteristics of the joint and cross-sectional strength of the bone shaft. Establishing the nature of the relationship between habitual joint function and the structure of trabecular bone within the joint will then allow researchers to more accurately reconstruct gait in fossil species. This project will apply its findings to one hypothesis about functional behavior in fossils, namely whether Neanderthals used their hands in ways that differed from those of modern humans. This research entails the most comprehensive analysis to date of higher primate trabecular bone structure. This research also has several important broader impacts. The scans obtained in this research will be made publicly available to foster additional research. At least one doctoral student will gain training from this project. It will help to develop a new approach to behavioral reconstruction that will be of interest to paleontologists outside of anthropology. Finally, this proposal will foster interdisciplinary research between a geologist and two physical anthropologists, and international collaboration between researchers in the U.S. and Japan.