Dottorato in BIOLOGIA AMBIENTALE ED EVOLUZIONISTICA

Titolo della tesi: Geometric Morphometrics and Functional Morphology applied to the study of skeletal remains from archaeological and modern samples

Bones are living tissue and can be considered an archive that records and stores an individual's biological and cultural data, providing direct evidence of the biology of past populations. Factors that occur and influence bones’ structure during the lifetime can be mechanical (e.g., activity levels and patterns) and non-mechanical (e.g., biological factors). Over the years, numerous methods have been proposed for reconstructing physical activities and mobility through the analysis of long bones diaphyseal morphology. Notably, analyses of the lower limb allow to observe the influence of lifestyle and mobility patterns, while the study of the upper limb aims to examine the presence of lateralisation (i.e., a preference for using one side over the other). This project aims to study cortical bone thickness and distribution in the diaphyses of femurs, tibiae, and humeri in a virtual environment. The sample under examination comprises CT scans of: i) recently deceased modern individuals selected from the forensic New Mexico Decedent Image Database: for each individual biological information and loading history are reported (e.g., occupations and physical activities); ii) archaeological skeletal remains from Classical and Early Medieval Italian cemeteries (Lucus Feroniae, RM; Povegliano Veronese; VR Selvicciola, VT), with a further application of the method proposed for some palaeopathological case studies from the same sites. The combined use of known modern and archaeological individuals offers the opportunity to consider, as comprehensively as possible, the study of variability within the sample, taking into account a broader range of factors. A new R package, morphomap, was applied and implemented. This approach aims not to limit the investigation to a few sections along the diaphysis but allow a detailed analysis of cortical bone distribution, thickness, and morphology along the entire diaphysis. The study is therefore potentially able to achieve a high degree of detail. Each cross-section is then analysed using an integrated approach that combines Cross-Sectional Geometry and Geometric Morphometrics, followed by multivariate statistics. The results of the explorative analyses are promising: the known modern sample allowed us to investigate which biological factors (specifically sex and age) most influence the morphology and thickness of cortical bone in the humeri, femurs, and tibiae. In particular, an interesting correlation was found within the age-specific women's sample, suggesting a possible occurrence of osteoporosis, but further analyses are needed to better explore this result. Finally, the application of this approach to some palaeopathological case studies was presented. For each case, a multidisciplinary investigation was applied allowing to reconstruct the individual's osteobiography. This thesis takes advantage of a known sample and an innovative technique. Its principal outcome is that the multidisciplinary approach overcomes data availability limitations and broadens possible interpretations. These results provide an efficient tool for future research in different disciplines, such as human evolution, primatology, and archaeology.