Martin Hora

Stature and body mass estimation from skeletal remains in the European Holocene

Techniques that are currently available for estimating stature and body mass from European skeletal remains are all subject to various limitations. Here, we develop new prediction equations based on large skeletal samples representing much of the continent and temporal periods ranging from the Mesolithic to the 20th century. Anatomical reconstruction of stature is carried out for 501 individuals, and body mass is calculated from estimated stature and biiliac breadth in 1,145 individuals. These data are used to derive stature estimation formulae based on long bone lengths and body mass estimation formulae based on femoral head breadth. Prediction accuracy is superior to that of previously available methods. No systematic geographic or temporal variation in prediction errors is apparent, except in tibial estimation of stature, where northern and southern European formulae are necessary because of the presence of relatively longer tibiae in southern samples. Thus, these equations should bebroadly applicable to European Holocene skeletal samples.

Gradual decline in mobility with the adoption of food production in Europe

Significance Declining mobility levels following the Pleistocene had profound effects on human demography, social organization, and health, but the exact timing and pace of this critical change are unknown. Here we examine direct evidence for changing mobility levels from limb bone structural characteristics in a large sample of European skeletons spanning the past 30,000 y. Our results show that mobility first declined during the Neolithic, at the onset of food production, but that the decline was gradual, continuing for several thousand years as agriculture intensified. No change in relative limb strength occurred during the past 2,000 y. Thus, the more gracile modern human skeleton is a result of increased sedentism tied to food production, not subsequent mechanization and industrialization. Increased sedentism during the Holocene has been proposed as a major cause of decreased skeletal robusticity (bone strength relative to body size) in modern humans. When and why declining mobility occurred has profound implications for reconstructing past population history and health, but it has proven difficult to characterize archaeologically. In this study we evaluate temporal trends in relative strength of the upper and lower limb bones in a sample of 1,842 individuals from across Europe extending from the Upper Paleolithic [11,000–33,000 calibrated years (Cal y) B.P.] through the 20th century. A large decline in anteroposterior bending strength of the femur and tibia occurs beginning in the Neolithic (∼4,000–7,000 Cal y B.P.) and continues through the Iron/Roman period (∼2,000 Cal y B.P.), with no subsequent directional change. Declines in mediolateral bending strength of the lower limb bones and strength of the humerus are much smaller and less consistent. Together these results strongly implicate declining mobility as the specific behavioral factor underlying these changes. Mobility levels first declined at the onset of food production, but the transition to a more sedentary lifestyle was gradual, extending through later agricultural intensification. This finding only partially supports models that tie increased sedentism to a relatively abrupt Neolithic Demographic Transition in Europe. The lack of subsequent change in relative bone strength indicates that increasing mechanization and urbanization had only relatively small effects on skeletal robusticity, suggesting that moderate changes in activity level are not sufficient stimuli for bone deposition or resorption.

The impact of subsistence changes on humeral bilateral asymmetry in Terminal Pleistocene and Holocene Europe

Analyses of upper limb bone bilateral asymmetry can shed light on manipulative behavior, sexual division of labor, and the effects of economic transitions on skeletal morphology. We compared the maximum (absolute) and directional asymmetry in humeral length, articular breadth, and cross-sectional diaphyseal geometry (CSG) in a large (n > 1200) European sample distributed among 11 archaeological periods from the Early Upper Paleolithic through the 20(th) century. Asymmetry in length and articular breadth is right-biased, but relatively small and fairly constant between temporal periods. Females show more asymmetry in length than males. This suggests a low impact of behavioral changes on asymmetry in length and breadth, but strong genetic control with probable sex linkage of asymmetry in length. Asymmetry in CSG properties is much more marked than in length and articular breadth, with sex-specific variation. In males, a major decline in asymmetry occurs between the Upper Paleolithic and Mesolithic. There is no further decline in asymmetry between the Mesolithic and Neolithic in males and only limited variation during the Holocene. In females, a major decline occurs between the Mesolithic and Neolithic, with resulting average directional asymmetry close to zero. Asymmetry among females continues to be very low in the subsequent Copper and Bronze Ages, but increases again in the Iron Age. Changes in female asymmetry result in an increase of sexual dimorphism during the early agricultural periods, followed by a decrease in the Iron Age. Sexual dimorphism again slightly declines after the Late Medieval. Our results indicate that changes in manipulative behavior were sex-specific with a probable higher impact of changes in hunting behavior on male asymmetry (e.g., shift from unimanual throwing to use of the bow-and-arrow) and food grain processing in females, specifically, use of two-handed saddle querns in the early agricultural periods and one-handed rotary querns in later agricultural periods.

Population-specific stature estimation from long bones in the early medieval Pohansko (Czech Republic).

OBJECTIVES We tested the effect of population-specific linear body proportions on stature estimation. MATERIALS AND METHODS We used a skeletal sample of 31 males and 20 females from the Early Medieval site at Pohansko (Břeclav, Central Europe) and a comparative Central European Early Medieval sample of 45 males and 28 females. We developed new population-specific equations for the Pohansko sample using anatomical reconstructions of stature, then compared percentage prediction errors (%PEs) of anatomical stature from limb bone lengths using the derived Pohansko equations with those previously derived from more general European and other Early Medieval samples. RESULTS Among general European equations, the lowest %PEs for the Pohansko sample were obtained using the equations of Formicola and Franceschi: Am J Phys Anthropol 100 (1996) 83-88 and Ruff et al.: Am J Phys Anthropol 148 (2012) 601-617. However, unexpectedly, the choice between tibial latitudinal variants proposed by Ruff et al.: Am J Phys Anthropol 148 (2012) 601-617 appeared to be sex-specific, with northern and southern variants producing lower %PEs for males and females, respectively. Equations from Breitinger: Anthropol Anz 14 (1937) 249-274, Bach: Anthropol Anz 29 (1965) 12-21, and Sjøvold: Hum Evol 5 (1990) 431-447 provided poor agreement with anatomical stature. When applied to the comparative Central European Early Medieval sample, our new formulae have generally lower %PE than previously derived formulae based on other European Early Medieval samples (Maijanen and Niskanen: Int J Osteoarchaeol 20 (2010) 472-480; Vercellotti et al.: Am J Phys Anthropol 140 (2009) 135-142. CONCLUSIONS The best agreement with anatomical stature among our newly developed equations was obtained using femoral+tibial length, followed by femoral length. Upper limb bone lengths resulted in higher %PEs. Variation in the tibia is likely to contribute most to potential bias in stature estimation. Am J Phys Anthropol 158:312-324, 2015.

Influence of body mass and lower limb length on knee flexion angle during walking in humans

Abstract. Despite abundant knowledge about the relationship between body size (i.e., body mass, lower limb length) and limb posture during locomotion on the level of interspecies variability, little is known about variation on the intraspecific level. We used an experimental approach to evaluate the relationship between body size and knee posture during walking in humans at specific gait events and at each percentage point of normalized stance phase. We detected significant negative correlation between knee flexion angle and body mass at the second peak of the vertical ground reaction force, but, in contrast to a previous study, we found no significant relationship between knee flexion angle and lower limb length. Although not significant, strengthened correlations between knee flexion angle and lower limb length were detected at late stance phase and these coincide well with the strengthened correlations between knee flexion angle and body mass. Our findings support the view that body size influences limb posture during locomotion even on the intraspecific level. In humans, larger individuals tend to use more extended knee postures in late stance of walking than do smaller individuals.

Body mass estimation in skeletal samples using the hybrid approach : the effect of population-specific variations and sexual dimorphism

Body mass is estimated from skeletal records with low accuracy, and it is expected that population-specific equations derived by a hybrid approach may help to reduce the error in body mass estimates. We used 204 individuals from five Central European Early Medieval sites to test the effect of population-specific femoral head breadth equations on the accuracy of body mass estimates. The baseline for living body mass was computed using the biiliac breadth and stature. We also analyzed the agreement of five general femoral head techniques that are used in body mass estimation (Elliott et al. (Archaeol Anthropol Sci 1–20, 2015b; Grine et al. (Am J Phys Anthropol 97:151–185, 1995); McHenry (Am J Phys Anthropol 87:407–431, 1992); Ruff et al. (Am J Phys Anthropol 148:601–617, 2012); Ruff et al. (Am J Phys Anthropol 86:397, 1991)). Our results support previous findings showing that body mass is predicted with lower accuracy than stature, even when population-specific equations are derived. However, the population-specific approach increases the agreement with the body mass estimated from the biiliac breadth and stature, particularly when sex-specific equations are used. Thus, our results advocate for the employment of sex-specific equations when possible and show that the possibility of deriving equation for each sex separately is the main advantage of the population-specific approach. The best agreement among the body mass techniques in the Central European Early Medieval samples was observed using the femoral head equations reported by Ruff et al. (Am J Phys Anthropol 148:601–617, 2012) and McHenry (Am J Phys Anthropol 87:407–431, 1992), whereas other studied equations provided lower agreement. The particularly low performance obtained using the technique reported by Elliott et al. (2015b) questioned the use of their equations to estimate body masses.

Population specificity of sex estimation from vertebrae

Vertebral measurements have been shown to provide accurate classification of sex. However, the use of vertebral discriminant functions (DFs) in forensic anthropology and bioarchaeology is limited due to the unknown degree of their population specificity. Additionally, the performance of vertebral DFs has not yet been assessed at higher posterior probability thresholds. In this study, we tested the performance of previously published DFs for sex classification from Th12 and L1 vertebrae within a range of 0.5-0.95 posterior probabilities in a model of geographically distant population based on an autopsy Central European (CE) sample (Czech Republic; n=72) from the 1930s. Further, we derived new pooled DFs from a sample representing ecogeographically diverse populations, new DFs derived from the autopsy CE sample, and new Medieval CE DFs derived from the Pohansko sample (n=129) and evaluated their performance at our testing autopsy CE sample. Most vertebral measurements showed population specificity in sex assessment. However, we identified two Th12 measurements (anteroposterior body diameter and mediolateral body diameter) usable for sex estimation across populations. We showed that the accuracy of vertebral DFs can be increased to 95% of correctly classified individuals in up to 64% of the studied sample by setting a higher posterior probability threshold. Finally, we showed that even the DFs derived from relatively small subsamples (30% of the population size) can provide accurate sex classification. This finding highlights the applicability of the hybrid approach in sex classification from vertebrae. To facilitate sex classification from vertebrae, we provide a software tool for sex classification from any vertebral measurement and reference samples tested in this study including the previously published DFs.