Resolving Pliocene and Pleistocene Hominin Ontogeny With Synchrotron Virtual Histology

探索人类生长和发育的进化对于理解现代人的独特属性，如漫长的童年和延长的生殖后期，具有特别重要的意义。尖端的x射线成像、发育生物学和化石记录分析的结合将揭示祖先人类遗骸中关于出生和随后生长的亲密记录。更广泛地说，这个项目将通过创建一个开放访问的虚拟古人类数据库，显著改善研究和教育基础设施。这将直接惠及那些无法获得原始标本和昂贵设备的学生和学者，以及基础设施有限、无法托管和传播大型虚拟数据集的非洲数据库。该项目还将加强和建立新的多学科国际合作，通过潜在地减少获取原始标本的需求来保护宝贵的化石材料，并为虚拟组织学新兴领域的学生和博士后提供研究和培训机会。由于其高度矿化的性质，牙齿是人类化石组合中最常见的元素。牙冠和牙根保存了年轻人日常生长、形成时间和死亡年龄的精确记录，数百万年来保持不变。重要的是，牙齿形成的时间是重建化石物种生长和发育的最准确的代理。这个项目将通过对早期古人类牙齿的研究来评估人类发展的进化。尖端的同步加速器成像将用于非破坏性地显示微观牙齿结构和三维（3D）。与之前的大多数研究不同，这些研究必须使用现存的猿类和/或人类的发育变量，这个项目将对尼安德特人之前的人类发展进行最全面和独立的评估。

Exploring the evolution of human growth and development is of particular significance for understanding unique attributes of modern humans, such as long childhoods and extended post-reproductive periods. The integration of cutting-edge X-ray imaging, developmental biology, and analyses of the fossil record will reveal the intimate record of birth and subsequent growth recorded in ancestral human remains. More broadly, this project will significantly improve research and education infrastructure through the creation of an open-access virtual hominin database. This will directly benefit students and scholars who are unable to access original specimens and costly equipment, as well as African repositories with limited infrastructure for hosting and disseminating large virtual datasets. The project also will also strengthen and establish novel multidisciplinary international collaborations, protect invaluable fossil material by potentially reducing the demand for access to original specimens, and provides research and training opportunities for students and a postdoctoral fellow in the emerging field of virtual histology.Due to their highly mineralized nature, teeth are the most common elements in human fossil assemblages. Tooth crowns and roots preserve precise records of daily growth, formation time, and age at death in young individuals, remaining unchanged for millions of years. Importantly, the timing of tooth formation is the most accurate proxy for reconstructing growth and development in fossil species. This project will assess the evolution of human development through the study of early hominin dentitions. Cutting-edge synchrotron imaging will be employed to reveal microscopic tooth structure non-destructively and in three-dimensions (3D). In contrast to most preceding studies, which necessarily employed living ape and/or human developmental variables, this project will yield the most comprehensive and independent assessment of development in hominins predating Neanderthals.