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Human variation in the Holocene

The aim of my morphological and metrical examination of human skeletal material research is to examine how the skeleton has changed over a known time period in response to environmental adaptation and genetic admixture. This research is focused on Iron and Bronze Age human skeletal remains from southern Africa (2000 BP, South Africa and Zambia), North Africa (3500-3000 BP, northern Sudan) and northern China (3000-1600 BP, near Beijing). Using statistics I compare measurements obtained from the archaeological samples with those from a related contemporary population. My initial results show that until very recently there was a greater amount of skeletal variation within these populations than previously thought. In addition to a better understanding on the amount of variation within the Holocene, this research can be used for cross regional and cultural (Iron vs Bronze Age) comparisons. The data was collected while I was a post-doctoral fellow at the University of the Witwatersrand (2009) and at Purdue University (2010-2011) and is now being prepared for publication.

Iron Age Southern Africans

On an Iron Age sample from Zambia in collaboration with others I conducted two published bioarchaeological studies; one of the post crania and crania, the other on the dentition. The sample was excavated between 1959 and 1965 by Fagan et al. and was the focus of a two volume series ‘Iron Age Cultures in Zambia’ (Fagan 1967; Fagan et al. 1969). From two archaeological sites Ingombe Ilede and Isamu Pati 56 human burials were found. Despite them being from different localities these sites are temporally, spatially and archaeologically related they are dated to the 7-15th centuries. They were threatened by development and excavated under rescue archaeology in the 60’s.

In collaboration with Professor T. Huffman and Dr. A. Gallagher at the University of the Witwatersrand we conducted a study on the bioarchaeological analyses of the human skeletons. We found that there was a high mortality rate for infants and children. Overall, most of the sample were younger than 35 years and had no indication of stress, trauma or infectious diseases. The low levels of cribra orbitalia and linear enamel hypoplasias indicate a low level of physiological stress, similar to that of contemporary populations in developed nations. There is no evidence of interpersonal violence or infectious diseases. Furthermore, this sample has no statistically significant differences in body mass or stature compared with contemporary South Africans. These data indicate a relatively healthy population with a well-balanced diet and low afflictions of infectious and parasitic diseases. For a more accurate assessment of health, however, the adult sample needs to be expanded.

The second study was done in collaboration with Dr. A-M Grimoud from Toulouse University in France. Wherein, we examined the adult dentition from these sites for evidence of pathology and trauma, as well as the levels and direction of tooth wear. Dental anthropology is an important area of study as teeth can be indicators of overall health and disease, while also providing some information on cultural practices. This study was innovative as we used radiography and morphology to determine pathology and trauma. The majority of pathologies were found with radiography alone, showing the necessity of using both radiography and morphology to fully understand the dental health in past populations. These people had very little pathology and trauma, dental modification of the maxillary incisors seemed to be a prominent risk factor for infection and inflammation. They had low levels of linear enamel hypoplasias and cavities; additionally we found root fractures in two teeth. The quantity of tooth wear has long been studied in past populations but the direction of wear is largely unrecorded. In our study we found sex differences in wear direction, which likely represents the use of teeth as tools for an activity restricted to one sex, but exactly which activity remains unknown.

To expand on these results I successfully applied for funding to explore teeth of Iron Age Southern Africans, to test if the health discovered above holds true in other samples. Building on the previous study above with the use of technologically advanced tools for examining teeth, microCT analyses was used. We have expanded our sample to 40 individuals from the Iron Age, with MicroCT our initial aim is to better visualise and quantify some of our previous findings, i.e. fractures and dental modifications. Then we plan to examine the teeth in their entirety from our new Iron Age samples. These microCT data were collected in the summer of 2014 in collaboration with Dr. Kristian Carlson and Dr. Tea Jashashvili at the Evolutionary Studies Institute, University of the Witwatersrand. With Dr. A-M Grimoud we are analysing these data. There are several opportunities for students on this study please contact me if you are interested.

To test the theory of health found in my earlier work on Iron Age people in southern Africa, I have successfully applied for a grant to expand my sample size to explore morphometrics across the skeleton and examine health.