These paleoenvironmental proxies sample past environments at geographic scales that are often regional. The GCFR flora is hyper-diverse, and glacial climate change-driven impacts on local vegetation could have been highly variable over relatively small geographic scales. Proxy records that are circumscribed in their geographic scale are thus key to our understanding of ancient environments at particular MSA archaeological localities.
Micromammal fossil teeth are now recognized as an abundant potential reservoir of paleoenvironmental proxy data at an extremely local scale. This study analyzed modern micromammal teeth obtained from raptor pellets at three locations on the south coast. Stable carbon isotope analysis indicates that the modern micromammals from the taxa sampled consume a wide range of δ13Cplant on the landscape when it is available, and thus stable carbon isotope analysis of micromammal teeth should act as a proxy for the range of available δ13Cdiet in a circumscribed area of vegetation.
Micromammal stable carbon isotope data obtained from specimens from one of the few well-dated MIS6-MIS5 sequences in the region (Pinnacle Point sites 13B, 30, and 9C). δ13Cenamel values for the taxa sampled indicate diets that are primarily C3, and there is almost no evidence for a dietary C4 grass component in any of the sampled specimens. This indicates that, at a minimum, pockets of C3 vegetation associated with the GCFR were likely available to hunter-gatherers at Pinnacle Point throughout the Middle and Late Pleistocene.
According to the dual diaspora model of Tiwanaku colonial organization in the Moquegua Valley of southern Peru, Chen Chen-style and Omo-style ethnic communities who colonized the valley maintained distinct ethnic identities in part through endogamous marriage practices. Biodistance analysis of cranial shape data is used to evaluate regional gene flow among Tiwanaku-affiliated communities in Moquegua. Overall, results of biodistance analysis are consistent with the dual diaspora model. Omo- and Chen Chen-style communities are distinct in mean cranial shape, and it appears that ethnic identity structured gene flow between ethnic groups. However, there are notable exceptions to the overall pattern, and it appears that marriage practices were structured by multiple factors, including ethnic affiliation, geographic proximity, and smaller scales of social organization, such as corporate kin groups.
Social network analysis of cranial shape data is used to implement a multi- and mesoscalar approach to social organization to assess family-based organization at a regional level. Results indicate the study sample constituted a social network comprised of a dense main component and a number of isolated actors. Formal approaches for identifying potential family groups (i.e., subgroup analysis) proved more effective than informal approaches. While there is no clear partition of the network into distinct subgroups that could represent extended kin networks or biological lineages, there is a cluster of closely related individuals at the core of the network who integrate a web of less-closely related actors. Subgroup analysis yielded similar results as agglomerative hierarchical cluster analysis, which suggests there is potential for social network analysis to contribute to bioarchaeological studies of social organization and bioarchaeological research in general.
This study tested hypotheses using two diet categorizations: total consumption percent and food material properties (FMPs). The first hypothesis that cortical bone area (CA) and section moduli (bone strength) are positively correlated with masticatory loading tests whether CA and moduli measures were greatest anteriorly and decreased posteriorly along the arch. The results found these measures adhered to this predicted pattern in the majority of taxa. The second hypothesis examines sutural complexity in the zygomaticotemporal suture as a function of dietary loading differences by calculating fractal dimensions as indices of complexity. No predictable pattern was found linking sutural complexity and diet in this primate sample, though hard object consumers possessed the most complex sutures. Lastly, cross-sectional geometric properties were measured to investigate whether bending and torsional resistance and cross-sectional shape are related to differences in masticatory loading. The highest measures of mechanical resistance tracked with areas of greatest strain in the majority of taxa. Cross-sectional shape differences do appear to reflect dietary differences. FMPs were not correlated with cross-sectional variables, however pairwise comparisons suggest taxa that ingest foods of greater stiffness experience relatively larger measures of bending and torsional resistance. The current study reveals that internal and external morphological factors vary across the arch and in conjunction with diet in primates. These findings underscore the importance of incorporating these mechanical differences in models of zygomatic arch mechanical behavior and primate craniofacial biomechanics.
I then test the practical application of this methodology by applying it to a mortuary sample including individuals from distinctive socioeconomic groups from the pre-Hispanic city of Teotihuacan, Mexico. The study recovers and uses the dietary isotope ratios within bone and tooth samples from 81 individuals buried throughout the city 1) to define the dietary correlates of wealth and status at Teotihuacan and 2) to identify individuals displaying lifetime dietary changes consistent with changes in socioeconomic status. In addition to supplementing our current understanding of Teotihuacan foodways and processes of geographic migration into the city, I identify an adult male individual from the La Ventilla B apartment compound who displays dietary changes throughout his life that are consistent with downward socioeconomic mobility from a high status socioeconomic group in early adolescence to an intermediate status group later in adulthood. I conclude by identifying ways to move forward with the comparative archaeology of socioeconomic mobility in premodern contexts and highlight the applicability of archaeological information to our understanding of present-day processes of social mobility.
The role that climate and environmental history may have played in influencing human evolution has been the focus of considerable interest and controversy among paleoanthropologists for decades. Prior attempts to understand the environmental history side of this equation have centered around the study of outcrop sediments and fossils adjacent to where fossil hominins (ancestors or close relatives of modern humans) are found, or from the study of deep sea drill cores. However, outcrop sediments are often highly weathered and thus are unsuitable for some types of paleoclimatic records, and deep sea core records come from long distances away from the actual fossil and stone tool remains. The Hominin Sites and Paleolakes Drilling Project (HSPDP) was developed to address these issues. The project has focused its efforts on the eastern African Rift Valley, where much of the evidence for early hominins has been recovered. We have collected about 2 km of sediment drill core from six basins in Kenya and Ethiopia, in lake deposits immediately adjacent to important fossil hominin and archaeological sites. Collectively these cores cover in time many of the key transitions and critical intervals in human evolutionary history over the last 4 Ma, such as the earliest stone tools, the origin of our own genus Homo, and the earliest anatomically modern Homo sapiens. Here we document the initial field, physical property, and core description results of the 2012–2014 HSPDP coring campaign.
We have little knowledge of how climatic variation (and by proxy, habitat variation) influences the phylogenetic structure of tropical communities. Here, we quantified the phylogenetic structure of mammal communities in Africa to investigate how community structure varies with respect to climate and species richness variation across the continent. In addition, we investigated how phylogenetic patterns vary across carnivores, primates, and ungulates. We predicted that climate would differentially affect the structure of communities from different clades due to between-clade biological variation. We examined 203 communities using two metrics, the net relatedness (NRI) and nearest taxon (NTI) indices. We used simultaneous autoregressive models to predict community phylogenetic structure from climate variables and species richness. We found that most individual communities exhibited a phylogenetic structure consistent with a null model, but both climate and species richness significantly predicted variation in community phylogenetic metrics. Using NTI, species rich communities were composed of more distantly related taxa for all mammal communities, as well as for communities of carnivorans or ungulates. Temperature seasonality predicted the phylogenetic structure of mammal, carnivoran, and ungulate communities, and annual rainfall predicted primate community structure. Additional climate variables related to temperature and rainfall also predicted the phylogenetic structure of ungulate communities. We suggest that both past interspecific competition and habitat filtering have shaped variation in tropical mammal communities. The significant effect of climatic factors on community structure has important implications for the diversity of mammal communities given current models of future climate change.
This study integrates osteological, biogeochemical, and archaeological data. Inherited dental and cranial features were used to examine biological relatedness and postmarital residence (biodistance analysis). Biochemical analysis of archaeological and modern samples was conducted to examine the geographic origins of the individuals buried in the cemetery and reconstruct mobility patterns. Osteological and biogeochemical data were interpreted in conjunction with archaeological and ethnographic/ethnohistoric data.
The results generally supported a relationship between spatial organization and biological relatedness based on phenotypic similarity at Tsepi. Postmarital residence analysis showed exogamous practices and tentatively supported higher male than female mobility. This practice, along with dietary inferences, could also be suggestive of maritime activities. Biogeochemical analysis showed a local character for the cemetery sample (96%). The common provenance of the three non-local individuals might reflect a link between Tsepi and a single locale. Burial location was not determined by provenance or solely by biological relatedness. Overall, the results point towards more nuanced reconstructions of mobility in prehistoric Aegean and suggest that burial location depended on a complex set of inter-individual relationships and collective identities. The contextualized bioarchaeological approach applied in this study added to the anthropological investigations of social practices such as kin relations (e.g., biological, marital, social kinship) and residential relocation as diachronic mechanisms of integration, adaptation, or differentiation.
This research examines the skeletal remains from a sacrificial deposit at the Epiclassic shrine site of Non-Grid 4 in the Basin of Mexico, where a minimum of 180 human crania were interred as ritual offerings. The project reconstructs patterns of paleomobility and biological relatedness to determine whether individuals with distinct categorical social identities were more likely to become victims of human sacrifice. It answers the questions: (1) Were the sacrificed individuals predominantly locals who lived in the Basin of Mexico throughout their lives?; (2) Were the sacrificed individuals comprised of a single kin-group biologically continuous with pre-extant populations in the Basin of Mexico?; and (3) If victims were migrants biologically discontinuous with antecedent populations, from where in ancient Mesoamerica did they originate?
Results indicate that a majority of sacrificial victims were immigrants originating north and south of the Basin of Mexico. Biogeochemical analyses of sacrificed individuals find that 80% are non-local migrants into the Basin, suggesting that they were likely targeted for violence based on their divergent residential histories. Multi-scalar biodistance analyses of Non-Grid 4 sacrificial victims demonstrate that they represent two biologically distinct groups. There was evidence, however, for both biological continuity among victims and pre-extant central Mexican populations, as well as for migration from northern and southern Mexico. This project therefore not only improves knowledge of migration during the central Mexican Epiclassic, but also contributes to broader anthropological understandings of the social context of violence.