Secular decline in cranioskeletal size over two millennia of interior central California prehistory: Relation to calcium deficit in the reconstructed diet and demographic stress

Abstract

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.

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

“…The large cranioskeletal size of SFBR Series 5-9 relative to SBC Series 1-4 is readily apparent in Table 1. Also notable is the fact that our oceanside Coast Miwok skeletons, Series 8-9, controlling for archaeological time, are on average slightly smaller than their presumed Miwok congeners in the Great Valley [2], but of about the same size as their bayside Miwok and Costanoan neighbours to the southeast [1]. The latter, not entirely unexpected, finding is of course accepted as further osteometric validation of the San Francisco Bay Indian physical type [1,30,33,53].…”

“…J. Osteoarchaeol. 8: 135-179 (1998) Channel; 34°N 23 28 48 23,23 23 22 23 23 23 n 23 23 23 n b -----2 The osteoarchaeological sample (Table 1) The skeletal material, usually well curated and restored, was drawn from museum collections of fairly well dated or phased archaeological specimens, a conscious effort being made to select for the anatomically more complete and better preserved adult same-individual sets of cranium, femurs and tibias, as explained in earlier reports [1][2][3][4]. The 14 osteometric series are grouped by cultural and natural area and latitude, rather than by time.…”

“…The osteometric -statistical methods used in the determination of the RR scores and the computation of the six specified bone volumes of each study series have been presented elsewhere, relating to archaeological San Francisco Bay and interior Central California in particular [1,2,4]. The RR-15 score (residual rickets score based on 15 diagnostic osteometric traits), elaborated from 35 direct measurements of cranial vault, cranial base, both femurs and both tibias, is a crude estimate of the intensity of the pattern of warping and stunting, due to endemic rickets during growth, persisting as a healed deformational sequel in the adult skeleton.…”

“…In recent osteometric studies of prehistoric Central California Indian cranioskeletal size [1,2], the osteophthisic or bone antitrophic influence of a chronic dietary calcium deficiency (CADEF) has been demonstrated quantitatively, together with the similar influence of demographic stress (DS, in the female). Presence during growth of either of these culturally determined conditions leads to a stunted and warped adult skeleton, deformed after the characteristic pattern of healed residual rickets (RR) [1][2][3]. The CADEF and DS related effects on the human skeleton, reversible in a matter of a few generations, are considered short-term.…”

Brief communication: Tissue isotopic enrichment associated with growth depression in a pig: Implications for archaeology and ecology

“…Significant correlations have been found between tissue isotopic enrichment of nitrogen and daily food ration size (Hobson et al, 1993;Focken, 2001;Gaye-Siessegger et al, 2003, water availability (Ambrose and DeNiro, 1987), diet quality (Hobson and Clark, 1992;Robbins et al, 2005), fasting (Hobson et al, 1993), and growth rate (Martinez del Rio and Wolf, 2005;Trueman et al, 2005). However, with few exceptions (e.g., White and Armelagos, 1997;Katzenberg and Lovell, 1999;Hedges and Reynard, 2007), consideration of nutritional or physiological stress in isotopic diet modeling has been limited to ecological studies, in spite of a considerable body of osteological literature on nutritional stress in archaeological populations (e.g., Angel, 1975Angel, , 1981Angel, , 1984Saul, 1977;Prendergast-Moore et al, 1986;White, 1988White, , 1999Danforth, 1994;Ubelaker, 1994;Ivanhoe, 1995;Larsen, 1997;Sobolik, 2002;Ortner, 2003).…”