Throughout the past, bioarchaeologists have been concerned with identifying subsistence strategies of past populations and when subsistence strategies have transitioned from foraging to agriculture practices. Specifically, one area of major concentration has been examining the transition from foraging to agriculture in the southeast of the present day United States. The present study examines the transition of subsistence practices in prehistoric Tennessee utilizing dental microwear texture analysis. This study examined a total of 49 individuals from Archaic and Mississippian sites. These were compared temporally by comparing Archaic microwear signatures to Mississippian microwear signatures, and geographically, through the comparison of each site in relation to its geographic location. Non-parametric Mann-Whitney U tests were utilized to determine if statistical significant differences existed between the Archaic and Mississippian groups analyzed, and to determine if statistical significant differences existed based on geographic location. Due to the small sample size utilized in the study, it must be stated that the results are preliminary and further testing using dental microwear texture analysis needs to be undertaken in order to better understand the results.

East Africa is central to many aspects of human evolution and diversification. At the same time, diet is a key aspect of the ecology of any population. Therefore, one is often interested in the diets of past populations. To assess human diet in the past, stable isotope ratio and dental microwear analyses are often perceived as the only semi-quantitative and objective techniques. However, there are still many unknowns on how isotopic and microwear signals change in response to dietary variation, because few controlled studies have been carried out in modern populations. To investigate this issue, this study targeted living humans from African ethnic groups (El Molo, Turkana, Luhya, and Luo, from Kenya, and Baka, from Cameroon) that practise a wide range of traditional subsistence strategies (pastoralism, fishing, and agriculture), with the objective of building a framework in which to consider past diet in an East African context. This study analysed human hair (n = 143), nail (n = 83), and breath (n = 186) for δ$^{13}$C and δ$^{15}$N from the six different communities, and dental moulds (n = 150) from five of those communities (no moulds were collected from the Baka), and related the findings to dietary information. Dental microwear analyses had a low success rate because microwear features were obscured by the biofilm produced by mouth bacteria. Nevertheless, a visual analysis of the results suggested that the El Molo have the hardest and the toughest diet among all the groups studied, possibly through the inclusion of abrasives in the diet during food processing. In turn, the isotopic analyses revealed the ways in which agriculturalists and hunter gatherers differ from pastoralists and fishers in their isotopic values, although the variation in δ$^{13}$C and δ$^{15}$N did not distinguish between pastoralists and fishers. The results emphasise recent changes in the diet of these groups, the importance of local factors in isotope values, and the variable sensitivity of isotopes to dietary practices. In conclusion, although each technique could provide complementary data that would contribute to a more inclusive view of diet, dental microwear analyses are not easily applied to modern human groups, due to the difficulty in acquiring comparative in vivo data, and in distinguishing between patterns caused by food items, or food processing techniques.

Dental microwear texture (DMT) analysis is used to differentiate abrasive dental wear patterns in many species fed different diets. Because DMT parameters all describe the same surface, they are expected to correlate with each other distinctively. Here, we explore the data range of, and correlations between, DMT parameters to increase the understanding of how this group of proxies records wear within and across species. The analysis was based on subsets of previously published DMT analyses in guinea pigs, sheep, and rabbits fed either a natural whole plant diet (lucerne, grass, bamboo) or pelleted diets with or without added quartz abrasives (guinea pigs and rabbits: up to 45 days, sheep: 17 months). The normalized DMT parameter range (P4: 0.69 0.25; M2: 0.83 0.16) and correlation coefficients (P4: 0.50 0.31; M2: 0.63 0.31) increased along the tooth row in guinea pigs, suggesting that strong correlations may be partially explained by data range. A comparison between sheep and guinea pigs revealed a higher DMT data range in sheep (0.93 0.16; guinea pigs: 0.47 0.29), but this did not translate into more substantial correlation coefficients (sheep: 0.35 0.28; guinea pigs: 0.55 0.32). Adding rabbits to an interspecies comparison of low abrasive dental wear (pelleted lucerne diet), the softer enamel of the hypselodont species showed a smaller data range for DMT parameters (guinea pigs 0.49 0.32, rabbit 0.19 0.18, sheep 0.78 0.22) but again slightly higher correlations coefficients compared to the hypsodont teeth (guinea pigs 0.55 0.31, rabbits 0.56 0.30, sheep 0.42 0.27). The findings suggest that the softer enamel of fast-replaced ever-growing hypselodont cheek teeth shows a greater inherent wear trace consistency, whereas the harder enamel of permanent and non-replaced enamel of hypsodont ruminant teeth records less coherent wear patterns. Because consistent diets were used across taxa, this effect cannot be ascribed to the random overwriting of individual wear traces on the more durable hypsodont teeth. This matches literature reports on reduced DMT pattern consistency on harder materials; possibly, individual wear events become more random in nature on harder material. Given the species-specific differences in enamel characteristics, the findings suggest a certain species-specificity of DMT patterns.

abstract: Dietary diversity is an important component of species’s ecology that often relates to species’s abundance and geographic distribution. Additionally, dietary diversity is involved in many hypotheses regarding the geographic distribution and evolutionary fate of fossil primates. However, in taxa such as primates with relatively generalized morphology and diets, a method for approximating dietary diversity in fossil species is lacking. One method that has shown promise in approximating dietary diversity is dental microwear analyses. Dental microwear variance has been used to infer dietary variation in fossil species, but a strong link between variation in microwear and variation in diet is lacking. This dissertation presents data testing the hypotheses that species with greater variation in dental microwear textures have greater annual, seasonal, or monthly dietary diversity. Dental microwear texture scans were collected from Phase II facets of first and second molars from 309 museum specimens of eight species of extant African Old World monkeys (Cercopithecidae; n = 9 to 74) with differing dietary diversity. Dietary diversity was calculated based on food category consumption frequency at study sites of wild populations. Variation in the individual microwear variables complexity (Asfc) and scale of maximum complexity (Smc) distinguished groups that were consistent with differences in annual dietary diversity, but other variables did not distinguish such groups. The overall variance in microwear variables for each species in this sample was also significantly correlated with the species’s annual dietary diversity. However, the overall variance in microwear variables was more strongly correlated with annual frequencies of fruit and foliage consumption. Although some variation due to seasonal and geographic differences among individuals was present, this variation was small in comparison to the variation among species. Finally, no association was found between short-term monthly dietary variation and variation in microwear textures. These results suggest that greater variation in microwear textures is correlated with greater annual dietary diversity in Cercopithecidae, but that variation may be more closely related to the frequencies of fruit and foliage in the diet. / Dissertation/Thesis / Doctoral Dissertation Anthropology 2015