Multi-proxy stable isotope analyses of dentine microsections reveal diachronic changes in life history adaptations, mobility, and tuberculosis-induced wasting in prehistoric Liguria (Finale Ligure, Italy, northwestern Mediterranean).

OBJECTIVE: To reconstruct breastfeeding and weaning practices, metabolic stress including tuberculosis-induced wasting, and residential mobility of children in Neolithic and Metal Ages to infer their local ecologies. MATERIALS: Seven permanent teeth from individuals dated to the Neolithic, Copper, Bronze, and Iron Ages buried in nearby caves in western Liguria, Italy. METHODS: Carbon, nitrogen, and sulfur stable isotope analyses on dentine microsections. Tooth maturation was used to calculate age at death. RESULTS: Two Neolithic children present longer pattern of weaning and appear to have been weaned using animal protein in contrast to the earlier weaning of Metal Ages children, which were probably weaned with vegetable resources. Sulfur isotopes suggest local origin of Neolithic and Cooper Age children, and non-local origins for Bronze and Iron Age children. Intense catabolism in the last two years is apparent in the adolescent with tuberculosis. CONCLUSIONS: Shortening in weaning patterns during the Metal Ages are likely driven by the intensification of agricultural practices and cultivation of new crops during Bronze and Iron Ages. Neolithic food choices and delayed weaning patterns may represent one of the strategies to maximize growth and immune potential in a local economy/ecology with high-infectious load. Tuberculosis was a chronic and long-lasting disease. SIGNIFICANCE: The first combined carbon, nitrogen, and sulfur analysis on prehistoric dentine microsections revealing changing human life history adaptations within the same region. LIMITATIONS: Small sample size. SUGGESTIONS FOR FURTHER RESEARCH: Increase the sulfur isotope dataset, use new EA-IRMS equipment, and provide data on amino acid to better define weaning food composition.

Environmental correlates of growth patterns in Neolithic Liguria (northwestern Italy).

OBJECTIVE: This study evaluates patterns of human growth in the Neolithic to make inferences about environmental correlates of developmental disturbances. MATERIALS: 33 children/adolescents from the Neolithic of Liguria (Italy), 29 of which date between 4,800-4,400 cal BCE. METHODS: Neolithic patterns of growth are compared with a modern sample (the Denver Growth Study; DGS). Dental development was used to determine age at death. Proxies for postcranial maturation are femoral length and proportion of mean adult femoral length attained. RESULTS: Ligurian children show growth faltering compared to DGS, especially between 4 and 9 years of age. Between 1 and 2 years, and in later childhood and adolescence, values are more similar or higher than DGS, when using the proportion of adult femoral length attained. CONCLUSIONS: The pattern of growth in Ligurian Neolithic children may reflect a deprived and highly-infectious environment: three individuals show skeletal lesions consistent with tuberculosis. The relatively faster growth in infancy may result from the buffering provided by maternal milk. Older children and adolescents may exhibit catch-up growth. SIGNIFICANCE: This study contributes to our understanding of Neolithic selective pressures and possible biocultural adaptive strategies. LIMITATIONS: The cross-sectional nature of the data and the small sample size make it unclear whether the observed pattern is representative of the growth patterns in the living population. The possibility that adults are stunted undermines the interpretation of optimal growth in the first years. SUGGESTIONS FOR FURTHER RESEARCH: Refine age estimates, increase sample size through the study of other bone elements.

Changes in skeletal robusticity in an iron age agropastoral group: the Samnites from the Alfedena necropolis (Abruzzo, Central Italy).

Cross-sectional geometrical (CSG) properties of an Iron Age Samnite group from the Alfedena necropolis (Abruzzo, Italy, 2600-2400 B.P.) are compared with a Ligurian Neolithic sample (6000-5500 B.P.). In the period under examination, Samnites were organized in a tribal confederation led by patrilinear aristocracies, indicating incipient social stratification. In comparison, Neolithic society lacked clear signs of social hierarchy. The subsistence of both groups was mainly based on pastoralism and agriculture, but changes in habitual behavior are expected due to the socio-economic transformations that characterized the Iron Age. The Samnites' warlike ideology suggests that unimanual weapon-use and training would have become frequent for males. The intensification of agriculture and the adoption of transhumant pastoralism, performed by a smaller subset of the population, likely led to a lower average level of logistic mobility. The strongly genderized ideology of the period suggests a strict sexual division of labor, with women primarily performing sedentary tasks. CSG properties based on periosteal contours were calculated for humeri, femora, and tibiae (N = 61). Results corroborated the expectations: Alfedena males show substantial humeral bilateral asymmetry, indicating prevalent use of one arm, likely due to weapon training. In both sexes lower limb results indicate reduced mobility with respect to the Neolithic group. Sexual dimorphism is significant in both humeral asymmetry and lower limb indicators of mobility. Although both groups could be broadly defined as agropastoral based on archeological and historical evidence, CSG analysis confirmed important differences in habitual behavior.

The importance of accounting for the area of the medullary cavity in cross-sectional geometry: A test based on the femoral midshaft.

In cross-sectional geometric (CSG) studies, both the subperiosteal and endosteal contours are considered important factors in determining bone bending rigidity. Recently, regression equations predicting CSG properties from a section's external dimensions were developed in a world-wide sample of human long bones. The results showed high correlations between some subperiosteally derived and actual CSG parameters. We present a theoretical model that further explores the influence of endosteal dimensions on CSG properties. We compare two hypothetical femoral midshaft samples with the same total subperiosteal area but with percentages of cortical bone at the opposite ends of published human variation for population sample means. Even in this relatively uncommon scenario, the difference between the samples in the resultant means for predicted femoral polar second moment of area (J) appears to be modest: power analysis indicates that a minimum sample size of 61 is needed to detect the difference 90% of the time via a t-test. Moreover, endosteal area can be predicted--although with substantial error--from periosteal area. Despite this error, including this relationship in subperiosteally derived estimates of J produces sample mean estimates close to true mean values. Power analyses reveal that when similar samples are used to develop prediction equations, a minimum sample of hundreds or more may be needed to distinguish a predicted mean J from the true mean J. These results further justify the use of regression equations estimating J from periosteal contours when analyzing behaviorally induced changes in bone rigidity in ancient populations, when it is not possible to measure endosteal dimensions. However, in other situations involving comparisons of individual values, growth trends, and senescence, where relative cortical thickness may vary greatly, inclusion of endosteal dimensions is still important.