How did our masticatory system evolve? Investigating bone and teeth microstructure in extant and fossil apes through X-ray synchrotron microtomography

牙齿和支撑它们的骨骼结构，下颌骨和上颌骨，是分类、生活史、生长速度、饮食和健康等进化信息的关键来源。然而，同步加速器射线照相等新技术通过提供有关内部和外部结构的微米级细节，揭示了信息的一个全新层面，从而使人们对多样性的模式和多样化的过程有了新的认识。这些新技术很少应用于原始人化石——我们的直系祖先以及现存的类人猿的祖先；Beaudet及其同事（2021年）对南方古猿化石的单一研究显示了它们的巨大潜力。在Beaudet与英国新钻石光源和Mirazon Lahr与肯尼亚国家博物馆合作的基础上，该项目旨在首次生成化石和当代非洲猿类（包括古人类）同步加速器x射线的大型比较数据集，并制定新的数据捕获和分析协议。通过这些，该项目将建立类人猿咀嚼系统不同元素生长速度的多样性，描述在分类学和生物学相关性的内部牙齿结构中观察到的多样性，提供未成熟标本的死亡年龄估计，这将大大提高我们对人类生活史进化的理解。

Teeth and the bony structures that support them, mandible and maxillae, are key sources of evolutionary information about taxonomy, life-history, growth rates, diet and health. Yet, new technologies, such as synchrotron radiography, are revealing a whole new dimension of information by providing micron-level detail on internal and external structures that throw new light on patterns of diversity and processes of diversification. These novel technologies have only rarely been applied to fossil hominids - our direct hominin ancestors as well as the ancestors of living great apes; the single study of an australopithecine fossil by Beaudet and colleagues (2021) shows their immense potential. This project aims at generating, for the first time, a large comparative dataset of synchrotron x-rays of fossil and contemporary African apes, including hominins, building on the collaboration by Beaudet with the new Diamond Light Source in the United Kingdom and Mirazon Lahr with the National Museums of Kenya, as well as develop new protocols of data capture and analysis. Through these, the project will establish the diversity in growth rates of different elements of the masticatory system of apes, describe the diversity observed in internal dental structures of taxonomic and biological relevance, provide age-atdeath estimates of immature specimens that will greatly enhance our understanding of the evolution of hominid lifehistories.