Stepwise discriminant function and Mahalanobis’ generalized distance analyses were applied to 29 cranial measurements in six female cranial series from the Ryukyu Islands and ten female cranial series representing modern and prehistoric Japanese and the Ainu. Two separate comparisons were made: the first compares Ryukyu Island cranial series and the second compares 16 cranial series from Japan. The results of this analysis have been used to investigate the biological relationships of the modern and near-modern indigenous inhabitants of the Ryukyu Islands and the modern and prehistoric inhabitants of Japan’s main islands. These new multivariate craniometric results are similar to those reported in a previous study that utilized male craniometric data. Overall, the Ryukyu cranial series are generally closest to a cluster consisting of Yayoi, Kofun, and medieval Kamakura cranial series, suggesting these populations were influenced by immigrants from the north. Modern Japanese, Jomon, and Ainu cranial series are well differentiated from each other and from the Ryukyu series. The Jomon are closest to the Ainu, and together these two are the most differentiated groups compared. As in the male results, the female results do not support a connection between Ainu, Jomon, and Ryukyu Island series.

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The aim of this work is to document secular changes in the head dimensions of Japanese adult females. The data set of the current study was compared with two others, one covering 1910–1917 and the other 1975–1979. The subjects of the present study were all of Japanese birth and ancestry, and were aged 18–25 years. Four head dimensions were measured: head length, head breadth, head height, and head circumference. The subjects’ height and body weight were also recorded. The mean head length, head breadth, and cephalic index were larger in the present study than in the 1910–1917 series. Head length, head height, and head size (circumference) were larger in the the current series than in the 1975–1979 series. However, head breadth and cephalic index in this series were somewhat larger than in the current series. Results of ANOVA showed significant differences (P < 0.01) for all birth-year cohorts from 1978 to 1983 in terms of head length, head breadth, and head circumference. Head height, cephalic index, height, and weight, however, did not display significant differences. Regression analysis revealed that all measurements, including the cephalic index, had decreased. These results indicate that although brachycephalization has been occurring for the last 85 years, the cephalic index has decreased over the last two decades in adult Japanese females.

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This study investigated the growth patterns of morphometric features of ancient people determined from historic and prehistoric skeletal remains. Subadult skeletons from the Yayoi, medieval, and modern periods were used. The age of each skeleton was estimated from dental formation standards. Measurement methods followed standard anthropological methodology established for the adult skeleton. Quadratic regression formulae that showed the highest coefficient of determination were chosen to evaluate plausible growth patterns. The results are as follows. (1) The neurocranium of the medieval people showed a possible difference in growth pattern compared with the modern people. The cause of this difference is discussed in relation to brachycephalization. (2) In all the groups studied here, over the course of growth, the height of the lower facial region increases much more than that of the upper facial region. With this change, the contour of the orbit changes into a relatively wider-lower shape, and the contour of the nasal cavity shifts with age from a relatively wider-lower to a narrower-higher condition. (3) In all the groups studied here, over the course of growth, the nasal bones become more curved transversely. However, the angle of the frontal process of the maxilla, which forms the lateral sides of the nasal bones, changes only slightly, if at all. (4) Secular differences in mandibular morphology related to chewing stress emerge at an older age than do the regional differences of the Yayoi people’s facial morphology, an effect that is probably related to genealogy. (5) Analysis of femur length suggests that the Yayoi people in the northern Kyushu and Yamaguchi region experienced less growth disruption than did the other people studied here.

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The class system in place during the Edo (early modern) period in Japan is thought to have included a range of customs that differed between the samurai (ruling class) and commoners. The incidence of caries in the dentition of the samurai was significantly lower than that of commoners. This difference is considered to be due to diet, eating frequency, and tooth care. As to location of the caries, it was found that the incidence of root caries in the samurai was remarkably lower than that in commoners. Root caries does not occur until gingival attachment recedes in an apical direction. The samurai and commoners did not show a significant difference in incidence of periodontal disease, while many samurai dentitions exhibited slick-polished teeth and wedge-shaped defects, which are thought to have been caused by the customary brushing of teeth. Such a custom might have successfully prevented dental caries. Given these findings, we consider that the lower incidence of caries in the samurai, compared with commoners, resulted from the influence of oral hygiene practices that helped to prevent root caries.

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To clarify bone formation and growth in Neanderthal children, we prepared a femoral midshaft cross-section of the Dederiyeh 1 Neanderthal child (ca. 2 years old) discovered in Syria, and compared its bone histomorphology with that of modern children aged 0–6 years. Bone histomorphometry was performed with regard to six parameters, i.e. cortical width, percent osteonal bone, osteon population density, non-Haversian canal population density, secondary osteon area, and Haversian canal area. Dederiyeh 1 had thick cortical bone similar to the mean of modern children aged 5–6 years, and advanced secondary bone formation, which was represented by greater percent osteonal bone and osteon population density than in 2-year-old modern children. However, primary bone configuration scarcely differed between Dederiyeh 1 and modern 1- to 2-year-olds. The histomorphology of the Dederiyeh 1 femur can be characterized as a complex of features seen in modern children at different ages, which suggests that cortical bone formation in Dederiyeh 1 was different from that in modern children. A variety of causes, such as mechanical loading, genetic control, and abnormal metabolism, are plausible, but it is not possible to determine which of these factors most affected bone formation in Dederiyeh 1.

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Pig and dog remains excavated from Fais Island in Micronesia were examined. The temporal distribution pattern of the excavated bones indicates that pigs and dogs have been kept on the island since at least 450 AD and possibly since around 220 AD. Both adult pigs and dogs were small in size. The majority of the excavated specimens were young or even juvenile. It is not clear if these animals were kept on Fais Island regularly or introduced from time to time. The possible source areas of pigs and/or dogs are the Philippines, Indonesia and northern Melanesia. The eastern Caroline Islands are another potential source area for the dogs.

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Vertebral assimilation was observed in an adult male Ainu skeleton from the Tokoro Chashi site of the early modern period in Tokoro, Hokkaido, Japan. The vertebral bodies and right zygapophyseal joint between the 12th thoracic and 1st lumbar vertebrae were completely united by osseous tissue, with anterior wedge shape and 42% loss of anterior vertebral body height. Differential diagnosis suggested that this was a healed state of pyogenic spondylitis.

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