Cranioskeletal Size Variation in San Francisco Bay Prehistory: Relation to Calcium Deficit in the Reconstructed High-seafoods Diet and Demographic Stress

An osteometric–statistical study of residual rickets (RR) skeletal plasticity has been made of a time-ordered sequence of 11 series of adult skeleton sets (n=251) from shellmound sites around San Francisco Bay (the Bay) spanning the three archaeological horizons of Central California Indian prehistory in this region: Early (EH), Middle (MH) and Late (LH). To control for major differences of subsistence ecology and ethnolinguistic affiliation, the Bay sequence was further subdivided into four subregions: East (EB, Costanoan), South (SB, Costanoan, high acorns), West (WB, Costanoan, low acorns) and Northwest (NWB, Coast Miwok). In the eight EB series, a non-linear downward trend in cranioskeletal size was observed between EH and LH2, coinciding with a modest upward trend in the RR-15B score. To ascertain if food calcium deficit (CADEF) can explain the observed secular decline in cranioskeletal size, the evolving aboriginal Bay archaeodiet—relatively high in marine mammals, birds, fish and calcium-rich mollusks—was reconstructed by the diet grid method: in the three subregions with large stands of oaks (EB, SB, NWB), CADEF rose from negligible in the EH to moderate in the LH, as the subsistence base became more dependent on leached acorn meal for energy. Temporal and areal variation in Bay cranioskeletal size relates mostly to CADEF, demographic stress in females (DS), and the ‘male nutritional advantage interaction co-factor’ (MNAIC), in descending order of importance. This study has also confirmed the existence of the San Francisco Bay Indian physical type.     

Archaeological Amerindian and Eskimo cranioskeletal size variation along coastal western North America: relation to climate,the reconstructed diet high in marine animal foods,and demographic stress

A quantitative bioenvironmental study of cranioskeletal size has been made of a latitude-ordered sequence of 14 series of adult skeleton sets (N=305): the archaeological remains of aboriginal maritime peoples inhabiting the west coast of North America between southern California and the Arctic. Of eight osteometric parameters of cranioskeletal size developed, the most important are partial skeleton volume (PSK) and cranial capacity (CC); and the principal bone-affecting environmental factors are the northerly climate (CLIM2c), the reconstructed diet deficient in calcium and overabundant in animal foods and vitamin D (DIET3c), and demographic stress (DSg). Prior research has demonstrated that cranioskeletal size increases with geographical latitude and decreases under dietary calcioprivation and unphysiologically high birth rates. Upon linear multifactorial statistical analysis our main finding, limited to the Amerindian subsequence (n=11 series) from the Santa Barbara Channel, the San Francisco Bay Region and the Northwest Coast, is that PSK and CC vary in direct proportion to CLIM2c, and inversely with DIET3c and DSg. Controlling for the latter two osteoantitrophic factors, coastal Amerindian female PSK rises by 9% between 34 and 54°N latitude, CC by 5%; and the male incremental rates are somewhat higher, 13 and 10%, respectively. This newly discovered climate-dependent race cline, an example of Bergmann's Rule, is interpreted as factual evidence of a mid-Wisconsin or earlier arrival date for the first Palaeoindians. Cranioskeletal size of the very small (n=3 series) Western Eskimo subsequence approximates the northernmost values of the coastal Amerindian distribution. © 1998 John Wiley & Sons, Ltd.     

Osteometric scoring of adult residual rickets skeletal plasticity in two archaeological populations from southeastern England: Relationship to sunshine and calcium deficits and demographic stress

An osteometric scoring technique is developed for the quantification of rickets deformational effects persisting in the healed adult skeleton. Termed RR-15 scoring (for residual rickets estimate, based on 15 main diagnostic osteometric traits), the method is first validated for sunshine deficit, and is then tested in a comparison of three climatically distinct archaeological populations from southeastern England. Two well-dated cemetery series were sampled: the Saint Bride's Church columbarium collection (SBC) from London at the time of the Industrial Revolution, for which the sex, age, and calender year at death of each individual are known; and the early Anglo-Saxons from Abingdon, near Oxford (AAS). Estimates of insolation in the past were developed indirectly by reference to δ¹⁸O mass spectrometer analyses of dated layers of the Greenland ice sheet. In SBC and AAS, the RR-15 score varies primarily as a direct function of computed sunshine deficit, but is also incremented by deficits of bioavailable calcium in their reconstructed diets, and by demographic stress in AAS, the inferred result of a high birth rate. The amounts of interglobular dentine present in the permanent first and third molar crowns of SBC and AAS have been shown to correlate similarly with sunshine and calcium deficits. The relatively high RR-15 score obtained in a small sample of northwestern European neanderthals lends quantitative support to the bioenvironmental hypothesis that sunshine-deficit rickets accounts for much of their paranormal gross morphology.     

Non‐specific indicators of stress and their association with age at death in Medieval York: Using stature and vertebral neural canal size to examine the effects of stress occurring during different periods of development

Selective mortality can occur towards individuals who survive episodes of physiological stress, such as disease and malnutrition, during development. The skeletal elements affected depend on the timing of these stressful episodes. Studying multiple non‐specific indicators of stress can show which periods of development were affected and whether certain periods can be linked with selective mortality. To examine this method a preliminary study of 61 adult individuals from the Medieval population of Fishergate House, York was undertaken to examine small vertebral neural canal size and reduced adult stature. Previous studies have shown that selective mortality occurs towards individuals who display these non‐specific indicators of stress. Statistical analysis showed that small transverse neural canal diameter was significantly associated with early adult mortality for males and females and there was evidence of selective mortality towards females with reduced stature. This suggests that individuals who died in early adulthood experienced health insults during late childhood which stunted VNC growth but males in particular were not significantly affected by health insults after this age as they achieved a normal adult stature. Therefore it appears that health insults which occurred during late childhood had a greater influence on adult health in the Fishergate House population. This method could be expanded to provide more detailed information by using a greater variety of non‐specific indicators of stress which will allow more specific periods of development to be investigated. Copyright © 2010 John Wiley & Sons, Ltd.