The intertrochanteric line on the proximal human femur has been the focus of paleoanthropological study for several decades, as it is thought to be a defining characteristic of bipedalism. Expression of this trait is highly variable in human fossils. However, the relatively narrow range of modern human groups in which its expression has been documented limits understanding of its variability and interpretation of its meaning. Our study analyzed variation in the expression of the intertrochanteric line in a population comprising young, middle and old age groups living in the 19th–20th centuries in Kunming city, southwestern China. Results showed that this trait was not equally present in all age groups. Statistical analyses revealed significant differences in frequencies of absence between the age groups, and also highlighted strong correlations between age and the degree of expression of the intertrochanteric line. It was more frequently absent or subtly expressed in young individuals, while individuals in the middle and old age groups tended to exhibit a more pronounced expression of this feature. The degree of expression of the intertrochanteric line also differed significantly between sexes, and it was significantly positively correlated with body size. Interestingly, the degree of expression of the intertrochanteric line rarely exhibited significant correlations with magnitudes of cross-sectional geometric properties of the femoral diaphysis, used as proxy measurements for physical activity patterns.

Studies have revealed the existence of statistically significant sex differences in the frequency of nonmetric traits, but no agreement seems to exist about their variability among populations. This problem was examined using the multifactorial threshold model. Considering the assumption of additive effects of factors on the liability and the nature of effect of sex difference on the development of nonmetric traits, it would be reasonable to assume that the sex difference in the mean of liability is constant across populations. This hypothesis was tested and the magnitude of sex difference was examined using the world-wide dataset collected by Ossenberg and the dual-liability threshold model formulated by the author with a modification to accommodate side difference in the probability of trait occurrence. The data were divided into 16 samples regarded as randomly sampled from regional populations. The data of 31 bilateral traits were analyzed using maximum likelihood estimation procedures. After confirming the homogeneity of the variance of liability between sexes and across populations, the homogeneity and significance of sex difference in the mean of liability were tested. The results indicate the homogeneity of sex difference across populations. The assumed constant sex difference was statistically significant in 17 traits at the 1% level, and its magnitude exceeded half the averaged distance between eight groups of populations in 12 traits. Population comparisons without distinguishing sex are justifiable if they use the traits with enough weak sex difference in comparison with population differences. Since the sex difference has proved to be basically constant across populations, the estimates of the assumed constant sex difference reported in this study would provide references for selecting traits appropriate for each comparison. The Breslow–Day test of homogeneity of sex difference indicated the inapplicability of the genotype model to the data, supporting Ossenberg’s proposal for the use of side counts.

Adaptation to various environments leads to evolutionary change in size and shape in non-human primates. In island environments, larger mammals tend to be smaller compared with the original mainland population. The Japanese macaque (Macaca fuscata) has two subspecies: Macaca fuscata yakui (MFY) on Yakushima Island, and Macaca fuscata fuscata (MFF) on the main Japanese archipelago. Since adult shape differences reflect spatiotemporal developmental pattern differences, it is interesting to examine allometric patterns for groups that show significant size variation. The main purpose of the present study is to quantitatively examine the craniofacial size and three-dimensional sexual and subspecies shape variation, focusing on the effects of size variation on shape variation. Computed tomography scans of 55 specimens were used to generate a three-dimensional model of each cranium, and 57 landmarks were digitized to quantify the craniofacial shape variation in Japanese macaques. We subsequently employed regression analyses to deduce vectors responsible for allometry, sex, subspecies shape variations, and the influence of size on sexual and subspecies shape variations. The results showed that four intraspecific groups, consisting of two subspecies and the two sexes, significantly differed in both size and shape space. In size, the cranium of MFY was smaller than that of MFF in both sexes, and female crania were smaller than male crania in both subspecies. Allometry as well as sexual dimorphism in shape was related to a relatively broad orbit, smaller neurocranium, enlarged snout, and broader temporal fossa in males. Subspecies shape differences were a relatively narrow and short orbit and sphenoid, smaller neurocranium, and postorbital constriction in MFY. Sexual shape variation was largely associated with size variation. On the other hand, subspecies shape variation was not significantly correlated with size. We discuss these intraspecific cranial size and shape variations and the effect of size on shape variation from evolutional and developmental perspectives.

The Pacopampa site is one of the largest Formative Period sites in Peru’s northern highlands. In the 2013 field season, we uncovered human remains from the stairs between the second and third platforms and found a rare case of a depressed skull fracture on the cranial vault of a middle-aged male. This study aims to describe the fracture and explore chronological changes in violence in Peru’s northern highlands. The radiocarbon date of this male is 910 ± 30 ¹⁴C yr BP, which corresponds to the Late Cajamarca Period (AD 950–1200). The fracture is elliptical in shape, 23.7 mm long and 23.3 mm wide. Depressed debris, adhering to part of the vault, entered the cranial cavity and may have compressed dura mater and brain substance. A healing reaction formed a smooth edge around the fracture, suggesting that it is an antemortem fracture and that the individual survived the injury. It is reasonable to infer that the presence of trauma on the Pacopampa cranium is consistent with the sociopolitical background, typified by high social tension and the appearance of organized warfare in Andean societies.