An osteometric study of residual rickets (RR) skeletal plasticity has been made of a timeordered sequence of fifteen series of adult skeleton sets (n=359) from the Great Valley of central California (GV), spanning the three archaeological horizons of California Indian prehistory in this region: Early (EH), Middle (MH) and Late (LH). By least-squares linear regression analysis, a clear and continuous downward trend obtained in cranioskeletal size in both sexes, proceeding from EH to LH in the GV sequence, paripassu with a steady upward trend in the RR-15 score. To ascertain if dietary calcium deficit (CADEF), a known cause of active rickets, can explain the observed secular increase in RR, the aboriginal diet was reconstructed by the diet grid method: CADEF was found to rise from borderline in the EH, to moderate in the MH, to severe in the LH, as the subsistence base shifted gradually away from hunted prey, and storable seed foods-mainly leached acorn meal-became the dominant source of energy. Further regression analysis has shown that the secular upward trend in CADEF is highly correlated with the temporal clines of the GV sequence, directly with the RR-15 score, and inversely with cranioskeletal size: in round numbers, one grade of CADEF brings about a loss of 120cm3 or 4 per cent in partial skeleton volume. Two biocultural influences -demographic stress (DS) in females, and the less common 'male nutritional advantage interaction co-factor' (MNAIC) -modulate the primary bone antitrophic CADEF effect: DS enhancing, MNAIC ameliorating.

Using computed femur (F) and tibia (T) volumes and cranial capacity (CC), the Pleistocene geomagnetic acromegalosis (PGMA) model of human evolution is tested in eight series of male skeleton sets (n = 123) from aboriginal North America and North Africa, the majority dated to the Holocene. The material was selected from the extensive multiracial osteometric data base previously assembled in the course of adult residual rickets (RR) skeletal plasticity research in archaeological populations of the Northern Hemisphere, controlling for optimal bone eutrophism, that is, for the absence of sunshine and calcium deficits and demographic stress. Six of the eight series are of hunter‐gatherers, including a terminal Pleistocene mesolithic sample from the Maghreb. As predicted by PGMA, a clear osteotrophic response is observed between the F, T, and CC of these populations and their geomagnetic dipole field intensity (GMFI) backgrounds, here expressed in microteslas (μT); along with evidence that the GMFI‐dependent osteotrophism is stronger near the sagittal plane. Slightly higher bioenvironmental correlations, also compatible with PGMA, are obtained with a composite environmental osteotrophism parameter (CEOT.J), which incorporates the reciprocal of the archaeological site's reconstructed mean July temperature as a synergizer of GMFI. In a final demonstration of the utility of the new computed osteovolumetrics, it is shown that Skhul IV, to judge from its size and proportions, is a hyperrobust pre‐neanderthal male skeleton of early Late Pleistocene interglacial age, and belongs to the North African geographical race.

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.

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 P O 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.

No abstract