No abstract

The power stroke of mastication has been traditionally divided into two parts, one which precedes centric occlusion, and the other which follows it --"Phase I" and "Phase II" respectively. Recent studies of primate mastication have called into question the role of "Phase II" in food processing, as they have found little muscle activity or accompanying bone strain following centric occlusion. That said, many researchers today look to "Phase II" facets to relate diet to patterns of dental microwear. This suggests the need to reevaluate microwear patterns on "Phase I" facets. Here we use texture analysis to compare and contrast microwear on facets representing both phases in three primate species with differing diets (Alouatta palliata, Cebus apella, and Lophocebus albigena).Results reaffirm that microwear patterns on "Phase II" facets better distinguish taxa by diet than do those on "Phase I" facets. Further, differences in microwear textures between facet types for a given taxon may themselves reflect diet.Some possible explanations for differences in microwear textures between facet types are proposed.

Dental microwear texture analysis has proven to be a valuable tool for inferring aspects of subsistence behaviour in human groups and diet in other mammals. Studies have to date been limited to molar teeth. Here we report on the first microwear texture analysis of incisors. Five bioarcheological groups were included in this analysis: Aleuts from various islands in the Bering Sea (n ¼ 24), Arikara from the Mobridge site in South Dakota (n ¼ 18), ethnic Chinese cannery workers from Kodiak Island (n ¼ 16), a Late Woodland Bluff sample from Jersey County, Illinois (n ¼ 18) and Puye Pueblo from Pajarito Plateau in New Mexico (n ¼ 18). First, point clouds with 0.18 mm lateral spacing and 0.005 mm vertical resolution were obtained from maxillary central incisor labial surfaces using a white-light confocal profiler. Four adjoining fields were sampled for a total area of 276 mm  204 mm for each specimen. Surface data were then imported into scale-sensitive fractal analysis software for texture characterisation.Results indicate significant variation among groups in anisotropy, fill volume and heterogeneity. These differences are likely related to differences in diet, degrees and types of nondietary incisor use, as well as exposure to abrasives. This study also suggests that texture variables most useful for characterising and comparing incisor microwear may differ from those most useful for distinguishing molar microwear patterns.

Here we describe dental remains from a Neanderthal fossil assemblage from Moula-Guercy, France. Our report demonstrates that the Moula-Guercy hominid remains contribute important morphological, developmental, and behavioral data to understanding Neanderthal evolutionary history. We include gross comparative morphological descriptions and enamel surface microstructure and microwear data. These teeth reveal numerous characteristics that are diagnostic of Neanderthals and provide no evidence for the presence of any other hominid taxa. Enamel growth increment data from the Moula-Guercy specimens yield evidence of a Neanderthal pattern of development, although at the lower end of the range of variation. The presence of a significant number of linear enamel hypoplasias indicates that these individuals were stressed during childhood. Molar microwear data suggest that these Neanderthals did not differ significantly from modern humans in terms of the fracture properties of the food they were consuming. The incisor microwear and macro striations provide evidence that these individuals may have been using their anterior teeth as tools, similar to the practices of several modern human populations such as the Inuit, Ipiutak, and Australian Aboriginals, and reminiscent of evidence from other Neanderthals from Krapina, Croatia, as well as the 600,000 year old hominids from Sima de los Huesos, Spain. Am J Phys Anthropol 151:477-491, 2013.© 2013 Wiley Periodicals, Inc.

Objectives The current study seeks to determine if a sample of foragers, farmers, and pastoralists are distinguishable based on their dental microwear texture signatures. Materials and methods The study included a sample of 719 individuals from 51 archeological sites (450 farmers, 192 foragers, 77 pastoralists). All were over age 12 and sexes were pooled. Using a Sensofar® white‐light confocal profiler we collected dental microwear texture analysis (DMTA) data from a single first or second molar from each individual. We leveled and cleaned data clouds following standard procedures and analyzed the data with Sfrax® and Toothfrax® software. The DMTA variables were complexity and anisotropy. Statistics included ANOVA with partial eta squared and Hedges's g. We also performed a follow‐up K‐means cluster analysis. Results We found significant differences between foragers and farmers and pastoralists for complexity and anisotropy, with foragers having greater complexity than either the farmers or the pastoralists. The farmers and pastoralists had greater anisotropy than the foragers. The Old World foragers had significantly higher anisotropy values than New World foragers. Old and New World farmers did not differ. Among the Old World farmers, those dating from the Neolithic through the Late Bronze Age had higher complexity values than those from the Iron Age through the medieval period. The cluster analysis discerned foragers and farmers but also indicated similarity between hard food foragers and hard food farmers. Discussion Our findings reaffirm that DMTA is capable of distinguishing human diets. We found that foragers and farmers, in particular, differ in their microwear signatures across the globe. There are some exceptions, but nothing that would be unexpected given the range of human diets and food preparation techniques. This study indicates that in general DMTA is an efficacious means of paleodietary reconstruction in humans.