Brief Communication: Intertooth and Intrafacet Dental Microwear Variation in an Archaeological Sample of Modern Humans From the Jordan Valley

Dental microwear was recorded in a Bronze-Iron Age (3570–3000 BP) sample of modern humans recovered from Tell es-Sa'idiyeh in the Jordan Valley. Microwear patterns were compared between mandibular molars, and between the upper and lower part of facet 9. The comparison revealed a greater frequency of pits and shorter scratches on the second and third molars, compared to the first. Pit frequency also increased on the lower part of the facet on the first molar, compared to the upper part. These results support previous calls for standardization when selecting a molar type for a diet-microwear study. Otherwise the microwear variations along the tooth row could mask any diet-microwear correlations. The results also suggest that there may be a need to choose a consistent location on a facet in order to enhance comparability among studies

Within-guild dietary discrimination from 3-D textural analysis of tooth microwear in insectivorous mammals

Resource exploitation and competition for food are important selective pressures in animal evolution. A number of recent investigations have focused on linkages between diversification, trophic morphology and diet in bats, partly because their roosting habits mean that for many bat species diet can be quantified relatively easily through faecal analysis. Dietary analysis in mammals is otherwise invasive, complicated, time consuming and expensive. Here we present evidence from insectivorous bats that analysis of three-dimensional (3-D) textures of tooth microwear using International Organization for Standardization (ISO) roughness parameters derived from sub-micron surface data provides an additional, powerful tool for investigation of trophic resource exploitation in mammals. Our approach, like scale-sensitive fractal analysis, offers considerable advantages over twodimensional (2-D) methods of microwear analysis, including improvements in robustness, repeatability and comparability of studies. Our results constitute the first analysis of microwear textures in carnivorous mammals based on ISO roughness parameters. They demonstrate that the method is capable of dietary discrimination, even between cryptic species with subtly different diets within trophic guilds, and even when sample sizes are small. We find significant differences in microwear textures between insectivore species whose diet contains different proportions of ‘hard’ prey (such as beetles) and ‘soft’ prey (such as moths), and multivariate analyses are able to distinguish between species with different diets based solely on their tooth microwear textures. Our results show that, compared with previous 2-D analyses of microwear in bats, ISO roughness parameters provide a much more sophisticated characterization of the nature of microwear surfaces and can yield more robust and subtle dietary discrimination. ISO-based textural analysis of tooth microwear thus has a useful role to play, complementing existing approaches, in trophic analysis of mammals, both extant and extinct

Dental Microwear From Natufian Hunter-Gatherers and Early Neolithic Farmers: Comparisons Within and Between Samples

Microwear patterns from Natufian hunter-gatherers (12,500–10,250 bp) and early Neolithic (10,250–7,500 bp) farmers from northern Israel are correlated with location on facet nine and related to an archaeologically suggested change in food preparation. Casts of permanent second mandibular molars are examined with a scanning electron microscope at a magnification of 500×. Digitized micrographs are taken from the upper and lower part of facet nine. Microwear patterns are recorded with an image-analysis computer program and compared within and between samples, using univariate and multivariate analyses. Comparisons within samples reveal a greater frequency of pits on the lower part of the facet among the farmers, compared to the upper part. Microwear does not vary over the facet among the hunter-gatherers. Comparisons between samples reveal larger dental pits (length and width) and wider scratches among the farmers at the bottom of the facet, compared to the hunter-gatherers. Microwear does not vary between samples at the top of the facet. The microwear patterns suggest that the Natufian to early Neolithic development led to a harder diet, and this is related to an archaeologically suggested change in food processing. The harder diet of the early farmers may have required higher bite forces that were exerted at the bottom of facet nine, in the basin of the tooth

Deciduous enamel 3D microwear texture analysis as an indicator of childhood diet in medieval Canterbury, England

This study conducted the first three dimensional microwear texture analysis of human deciduous teeth to reconstruct the physical properties of medieval childhood diet (age 1-8yrs) at St Gregory's Priory and Cemetery (11th to 16th century AD) in Canterbury, England. Occlusal texture complexity surfaces of maxillary molars from juvenile skeletons (n=44) were examined to assess dietary hardness. Anisotropy values were calculated to reconstruct dietary toughness, as well as jaw movements during chewing. Evidence of weaning was sought, and variation in the physical properties of food was assessed against age and socio-economic status. Results indicate that weaning had already commenced in the youngest children. Diet became tougher from four years of age, and harder from age six. Variation in microwear texture surfaces was related to historical textual evidence that refers to lifestyle developments for these age groups. Diet did not vary with socio-economic status, which differs to previously reported patterns for adults. We conclude, microwear texture analyses can provide a non-destructive tool for revealing subtle aspects of childhood diet in the past

Human Dental Microwear From Ohalo II (22,500–23,500 cal BP), Southern Levant

Dietary hardness and abrasiveness are inferred from human dental microwear at Ohalo II, a late Upper Palaeolithic site (22,500–23,500 cal BP) in the southern Levant. Casts of molar grinding facets from two human skeletons were examined with a scanning electron microscope. The size and frequency of microwear was measured, counted, and compared to four prehistoric human groups from successive chronological periods in the same region: pre-pottery Neolithic A, Chalcolithic (this study); Natufian, pre-pottery Neolithic B (Mahoney: Am J Phys Anthropol 130 (2006) 308–319). The Ohalo molars had a high frequency of long narrow scratches, and a few small pits, suggesting a tough abrasive diet that required more shearing rather than compressive force while chewing. These results imply that the diet of the two late Upper Palaeolithic hunter-gatherers did not focus on very hard foods. Aquatic foods with adherent contaminants, as well as grit from plant grinding tools seemed likely causal agents. The size of the pits and scratches on the Ohalo molars were most similar to microwear from the pre-pot- tery Neolithic A period, though they also compared well to the Chalcolithic period. These results contrasted with the larger pits and scratches from the Natufian hunter-gath- erers and pre-pottery Neolithic B farmers, implying that there is no simple increase or decrease in dietary hard- ness and abrasiveness across the late Upper Palaeolithic to Chalcolithic development in the Southern Levant

Effects of Instrumentation on Dental Microwear Textures: Reanalysis and Augmentation of an Early Hominin Sample

Dental microwear texture analysis has been refined to a methodology relying upon scanning confocal microscopy for its advantages of repeatability and standardized quantification. A new instrument, the Plu Neox (Sensofar Corp.) confocal profiler recently entered the market, sparking questions among dental anthropologists related to the advantages and efficacy of this new technology, which has better resolution and lighting properties than previously available white-lighted based confocal profilers. This thesis reports on three complementary studies that set out to evaluate the comparability of the Plu Neox to the Plu Standard system and assess its ability to distinguish primates on the basis of their microwear patterning. The first study examines a sample of hominin molars (Australopithecus africanus and Paranthropus robustus) for comparison with data previously scanned and analyzed on the University of Arkansas\u27 Plu Standard confocal microscope (Scott et al., 2005). The second study expands the sample of early hominins to determine whether an enlarged sample of A. africanus continues to show significant texture separation from P. robustus. And the third study examines extant primate microwear textures of pitheciids with known dietary differences to determine whether documented food-choice trends are reflected in microwear patterning obtained using the Plu Neox. Examining pitheciine molar facets in the past was not possible because of their small size. The new instrument provides higher resolution (0.11 um with a 150x objective compared to 0.18 um at 100x on the Plu Standard confocal), with a smaller work envelop for a comparable number of sampled points for texture analysis. Results of the first study generally correspond to the original texture analysis of 2005, and the expanded dataset in the second study shows increased variance but the same pattern of differences for A. africanus compared with P. robustus. The third study finds that the Plu Neox is capable of parsing broad diet-related differences in microwear textures among the pitheciids, indicating that the new instrument may become an effective instrument for the quantitative characterization and comparison of dental microwear textures to be utilized in laboratories around the world

‘Do larger molars and robust jaws in early hominins represent dietary adaptation?’ A New Study in Tooth Wear

Diet imposes significant constraints on the biology and behaviour of animals. The fossil record suggests that key changes in diet have taken place throughout the course of human evolution. Defining these changes enables us to understand the behaviour of our extinct fossil ancestors. Several lines of evidence are available for studying the diet of early hominins, including craniodental morphology, palaeoecology, dental microwear and stable isotopes. They do, however, often provide conflicting results. Using dental macrowear analysis, this new UCL Institute of Archaeology project will provide an alternative source of information on early hominin diet. Dental macrowear has often been used to analyse diet in archaeological populations, but this will be the first time that this type of detailed study has been applied to the early hominin fossil record

Molar macrowear reveals Neanderthal eco-geographic dietary variation

Neanderthal diets are reported to be based mainly on the consumption of large and medium sized herbivores, while the exploitation of other food types including plants has also been demonstrated. Though some studies conclude that early Homo sapiens were active hunters, the analyses of faunal assemblages, stone tool technologies and stable isotopic studies indicate that they exploited broader dietary resources than Neanderthals. Whereas previous studies assume taxon-specific dietary specializations, we suggest here that the diet of both Neanderthals and early Homo sapiens is determined by ecological conditions. We analyzed molar wear patterns using occlusal fingerprint analysis derived from optical 3D topometry. Molar macrowear accumulates during the lifespan of an individual and thus reflects diet over long periods. Neanderthal and early Homo sapiens maxillary molar macrowear indicates strong eco-geographic dietary variation independent of taxonomic affinities. Based on comparisons with modern hunter-gatherer populations with known diets, Neanderthals as well as early Homo sapiens show high dietary variability in Mediterranean evergreen habitats but a more restricted diet in upper latitude steppe/coniferous forest environments, suggesting a significant consumption of high protein meat resources

Methodological implications of intra- and inter-facet microwear texture variation for human childhood paleo-dietary reconstruction: Insights from the deciduous molars of extant and medieval children from France

The present study concerns occlusal dental microwear texture variation on the deciduous molars of children. A description and evaluation of microwear texture variation within facet 9 and a comparison of microwear textures between grinding facets 9 and 11 are presented. The relationship between wear facet surface area and intra-facet microwear texture variability is evaluated. The sample is composed of naturally-exfoliated, taphonomy-free deciduous second molars from twelve extant children and four archaeologically-derived medieval children (for a total of 51 surface measurements). Dental microwear texture analysis (DMTA) was performed using a confocal microscope and scale-sensitive fractal analysis (SSFA) at three standardized locations on facet 9, and one location on facet 11. Facet shape was visually assessed and scored using a headset magnifier (3×) and composite images (20× confocal microscopy). Individuals were assigned to two groups based on a qualitative assessment of facet surface area. Microwear texture variability within facet 9 was high relative to the variability of microwear textures between individuals. No significant inter-facet variation between facets 9 and 11 was detected. No clear differences in microwear and variabilities within facet 9 were found between individuals assigned to small and large facet groups. Our study shows the existence of important intra-facet microwear variation in a sample of children. Intra-facet microwear variation can affect the ability of DMTA to distinguish between diets in contexts with small sample sizes and subtle differences in diet – such as those characterizing dietary transitions in children. Results also suggest non-dietary factors may influence microwear formation during dental exfoliation. A better understanding of intra-facet microwear variation, and when and how to account for it, can improve the application of occlusal DMTA in similar contexts