Wiley

A new method for the determination of adult skeletal age at death based upon chronological changes in the auricular surface of the ilium is presented. Formal stages have been constructed following extensive tests and refinements in observations made of such changes. Two completely “blind” tests were conducted to assess the accuracy and bias of the new method. Results show that the system is equally accurate to pubic symphyseal aging (although somewhat more difficult to apply), and also carries the advantages of a higher preservation rate for the auricular surface in archaeological populations and continued age‐related change beyond the fifth decade.

The aim of this study was to develop a comprehensive evidence‐based atlas to estimate age using both tooth development and alveolar eruption for human individuals between 28 weeks in utero and 23 years. This was a cross‐sectional, retrospective study of archived material with the sample aged 2 years and older having a uniform age and sex distribution. Developing teeth from 72 prenatal and 104 postnatal skeletal remains of known age‐at‐death were examined from collections held at the Royal College of Surgeons of England and the Natural History Museum, London, UK (M 91, F 72, unknown sex 13). Data were also collected from dental radiographs of living individuals (M 264, F 264). Median stage for tooth development and eruption for all age categories was used to construct the atlas. Tooth development was determined according to Moorrees et al. (J Dent Res 42 (1963a) 490–502; Am J Phys Anthropol 21 (1963b) 205–213) and eruption was assessed relative to the alveolar bone level. Intraexaminer reproducibility calculated using Kappa on 150 teeth was 0.90 for 15 skeletal remains of age <2 years, and 0.81 from 605 teeth (50 radiographs). Age categories were monthly in the last trimester, 2 weeks perinatally, 3‐month intervals during the first year, and at every year thereafter. Results show that tooth formation is least variable in infancy and most variable after the age of 16 years for the development of the third molar. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc.

Tooth wear records valuable information on diet and methods of food preparation in prehistoric populations or extinct species. In this study, samples of modern and prehistoric hunter–gatherers and agriculturalists are used to test the hypothesis that there are systematic differences in patterns of tooth wear related to major differences in subsistence and food preparation. Flatness of molar wear is compared for five groups of hunter–gatherers (N = 298) and five groups of early agriculturalists (N = 365). Hunter–gatherers are predicted to develop flatter molar wear due to the mastication of tough and fibrous foods, whereas agriculturalists should develop oblique molar wear due to an increase in the proportion of ground and prepared food in the diet.

A method is presented for the quantitative measurement and analysis of flatness of molar wear. Comparisons of wear plane angle are made between teeth matched for the same stage of occlusal surface wear, thus standardizing all groups to the same rate of wear. Agriculturalists develop highly angled occlusal wear planes on the entire molar dentition. Their wear plane angles tend to exceed hunter–gatherers by about 10° in advanced wear. Wear plane angles are similar within subsistence divisions despite regional differences in particular foods. This approach can be used to provide supporting evidence of change in human subsistence and to test dietary hypotheses in hominoid evolution.

The postcranial skeleton of Australopithecus afarensis from the Hadar Formation, Ethiopia, and the footprints from the Laetoli Beds of northern Tanzania, are analyzed with the goal of determining (1) the extent to which this ancient hominid practiced forms of locomotion other than terrestrial bipedality, and (2) whether or not the terrestrial bipedalism of A. afarensis was notably different from that of modern humans. It is demonstrated that A. afarensis possessed anatomic characteristics that indicate a significant adaptation for movement in the trees. Other structural features point to a mode of terrestrial bipedality that involved less extension at the hip and knee than occurs in modern humans, and only limited transfer of weight onto the medial part of the ball of the foot, but such conclusions remain more tentative than that asserting substantive arboreality. A comparison of the specimens representing smaller individuals, presumably female, to those of larger individuals, presumably male, suggests sexual differences in locomotor behavior linked to marked size dimorphism. The males were probably less arboreal and engaged more frequently in terrestrial bipedalism. In our opinion, A. afarensis from Hadar is very close to what can be called a “missing link.” We speculate that earlier representatives of the A. afarensis lineage will present not a combination of arboreal and bipedal traits, but rather the anatomy of a generalized ape.

We have measured the ¹⁴C content of human femoral mid‐shaft collagen to determine the dynamics of adult collagen turnover, using the sudden doubling and subsequent slow relaxation of global atmospheric ¹⁴C content due to nuclear bomb testing in the 1960s and 1970s as a tracer. ¹⁴C measurements were made on bone collagen from 67 individuals of both sexes who died in Australia in 1990‐1993, spanning a range of ages at death from 40 to 97, and these measurements were compared with values predicted by an age‐dependent turnover model. We found that the dataset could constrain models of collagen turnover, with the following outcomes: 1) Collagen turnover rate of females decreases, on average, from 4%/yr to 3%/yr from 20 to 80 years. Male collagen turnover rates average 1.5–3%/yr over the same period. 2) For both sexes the collagen turnover rate during adolescent growth is much higher (5–15%/yr at age 10–15 years), with males having a significantly higher turnover rate than have females, by up to a factor of 2. 3) Much of the variation in residual bomb ¹⁴C in a person's bone can be attributed to individual variation in turnover rate, but of no more than about 30% of the average values for adults. 4) Human femoral bone collagen isotopically reflects an individual's diet over a much longer period of time than 10 years, including a substantial portion of collagen synthesised during adolescence Am J Phys Anthropol, 2007. © 2007 Wiley‐Liss, Inc.

Measurements were taken on the upper and lower molars of 37 species of primates and one tupaiid to assess the relative importance of shearing, crushing and grinding features.

Significant correlations were found between pairs of allometrically standardized dimensions which measure the same molar function (shearing, crushing, or grinding). Correlations between pairs of dimensions which do not measure the same function are not significant.

Second molar adaptations for shearing, crushing, and grinding, as well as the length of the second lower molar, and the total surface of the post‐canine dentition are negatively allometric with respect to metabolic rate.

Species which take different proportions of fruit, leaves, and insects in their diets have different molar structure. Frugivores have small teeth for their adult body size with poorly developed shearing, crushing, and grinding features on their molars. By contrast, leaf‐eating species tend to have large teeth for their adult body size with well developed shearing, crushing, and grinding. The second molars of insectivorous species were found to parallel closely those of leaf‐eating species. The two groups are clearly distinguishable from the former on the basis of body size alone: the smallest living primate leaf‐eater is on order of magnitude larger than the largest living primate insectivore.

Among primitive peoples dental attrition appears to be a natural phenomenon. Often the degrees and kinds of tooth wear vary from population to population. This variability is possibly related to certain material aspects of culture such as diet, food preparation techniques and tool usage. In order to learn more about these relationships, extensive cross cultural comparisons must be made.

This paper reports on a study of dental attrition among skeletal remains of North American Indians from three areas: California, the Southwest and the Valley of Mexico. A method of comparing worn teeth of these populations was devised so several characteristics of the teeth and supporting bone could be examined by population. This study showed significant differences in type and degree of wear among the three groups as well as differences between sexes within each population.

A positive correlation between tooth wear and cultural factors was found. Dietary specialization and division of labor appear to be responsible for the degree and type of wear found in this sample. Further studies of this type are planned to expand the sample size and, if the new data support these correlations, valuable information about human–environmental relationships can be gained.

Carbon (¹³C/¹²C) and nitrogen (¹⁵N/¹⁴N) stable isotope ratios were longitudinally measured in fingernail and hair samples from mother‐infant pairs where infants were exclusively breastfed (n = 5), breast‐ and formula‐fed (n = 2), or exclusively formula‐fed (n = 1) from birth. All exclusively breastfed infants had a dual enrichment in carbon (≈1‰) and nitrogen (≈2–3‰) when compared to maternal values. In contrast, breast‐ and formula‐fed subjects had reduced enrichments compared to exclusively breastfed subjects, and the exclusively formula‐fed infant showed no increase in δ¹³C or δ¹⁵N values. This finding of a carbon trophic level effect in breastfeeding infants suggests that ¹³C‐enrichments of approximately 1‰ in archaeological populations are not necessarily the result of the consumption of C₄‐based weaning foods such as maize or millet. During the weaning process, the δ¹³C results for breastfed infants declined to maternal levels more rapidly than the δ¹⁵N results. This suggests that δ¹³C values have the potential to track the introduction of solid foods into the diet, whereas δ¹⁵N values monitor the length of time of breast milk consumption. These findings can be used to refine the isotopic analysis of breastfeeding and weaning patterns in past and modern populations. Am J Phys Anthropol, 2006. © 2005 Wiley‐Liss, Inc.