Doctoral Dissertation Improvement: Human Growth Evolving: Integrating Skeletal, Dental, and Cranial Proxies of Growth to Understand Ontogeny in Pleistocene Genus Homo

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Modern humans are characterized by a very slow pattern of growth and development (i.e. ontogeny) compared to the closest living relatives, the chimpanzees. In hard tissues this trend is evident in late eruption of teeth and late attainment of skeletal maturity. This delayed maturation is necessary for the development of large brains, and mastering bipedal locomotion and language, but it is still uncertain when this pattern arose during the evolution of the human lineage. Most studies of modern human and fossil ontogeny have focused on either dental or skeletal development, using the other developmental system as an age proxy. However, for a proper understanding of the origins of the modern human ontogenetic pattern, and its implications for human evolution, it is critical to understand not only the relationship between dental and skeletal growth, but also the timing of developmental events.This study will address this issue by combining data on dental and skeletal growth and development in modern human skeletal samples from different geographic regions. It will include data on dental formation and eruption, several cranial maturity indicators, epiphyseal fusion, and long bone lengths and diameters, and relate them to chronological age wherever possible. Several Pleistocene fossils belonging to H. erectus, Neanderthals, and early H. sapiens, whose age-at-death will be estimated from dental microstructure, will be compared to modern humans of similar age to see whether they share a common pattern and timing of dental and/or skeletal growth and development.The broader implications of this study include the first attempt to compare dental and skeletal growth and development in fossils to a large and diverse modern human sample, and to relate it to chronological age. Furthermore, the large modern human sample will be useful for re-evaluation and refinement of osteological standards. This research will contribute to the doctoral dissertation and training of a female graduate student. Finally, this project will foster international collaboration between the United States and institutions in Africa, Asia, and Europe.