Anthropological Science (Japanese Series)
Online ISSN : 1348-8813
Print ISSN : 1344-3992
ISSN-L : 1344-3992
Volume 112, Issue 2
Displaying 1-4 of 4 articles from this issue
Original Articles
  • Hiroyuki Yamada, Shintaro Kondo, Hajime Hanamura
    2004 Volume 112 Issue 2 Pages 75-84
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    The tooth germs of the third molars grow up at the latest stages of ontogeny in the human dentition, and the teeth show the highest frequencies in congenitally missing teeth. Moreover, the third molar in the dentition is subjected to change easily in the course of microevolution. The frequencies of the third molar agenesis were investigated in this study to evaluate their secular changes in the microevolution of the Japanese populations.
    The results are as follows: the third molar agenesis are considerably low in incidence for the peoples of the Jomon Era, but the incidence in the people from the Yayoi Era suddenly turned to increase, although higher food intake due to rice cultivation may be expected as compared with that of the Jomon Era. This rapid change in frequency is considered to be caused by the gene flows from the immigrants from the Asian Continent with the congenitally missing third molar teeth at a higher rate of incidence. From the Yayoi Era, the frequencies of the third molar agenesis increased gradually and reached to the peak in the percentage at the beginning of the Showa Era. After that period, the frequencies decreased rapidly up to the present. The reasons for this rapid change are the food intake with high nutrition and high protein as well as the change of life environments, which have also caused the higher stature and the acceleration of sex maturation.
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  • Basic Morphological and Statistical Analyses
    Kentaro Tanaka, Junmei Sawada, Kazuhiro Sakaue, Yukio Dodo
    2004 Volume 112 Issue 2 Pages 85-100
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    The talar joint facets of the calcaneus were classified into 5 types according to their configuration: single facet type, continuous type, demarcated type, separate type, and no anterior facet type. Side association, side difference, sex difference, and age change in the incidence of occurrence of the 5 types, and association between the morphological classifications of the joint surfaces of the calcaneus and talus were investigated using a dissecting room Japanese skeletal series of known sex and age. Measurements were also taken for the length and depth of the anterior and middle talar facets of the calcaneus. The results showed that 1) Each individual type of talar joint facet was highly associated by side; 2) No side difference in trait incidence was found; 3) The sex difference in trait incidence was significant at the 5% level; 4) No age change in trait incidence from the young adult to the elderly was found; 5) A strong association was observed between the calcaneal and talar joint facet configurations: continuous vs. smooth, demarcated vs. angular, and separate vs. grooved; and 6) The depth of the anterior and middle talar facets of the calcaneus was greater in the separate type. Taking these results and the results of previous studies into consideration, it is concluded that the morphological variation in talar joint facets of the calcaneus may be regarded as not only one of the infracranial nonmetric traits under genetic control, but also a trait of some functional significance.
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  • Temporal and Regional Differences in Japanese Islanders
    Kentaro Tanaka, Junmei Sawada, Kazuhiro Sakaue, Yukio Dodo
    2004 Volume 112 Issue 2 Pages 101-111
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    Incidences of the "Separate Type" of anterior and middle talar joint surfaces were compared between Jomon, Yayoi, Hokkaido Ainu, and modern main-islands Japanese calcaneal samples. The results showed that 1) In modern Japanese samples, incidences of this trait ranged between 34.7% and 39.8%, and no regional difference in incidence was observed; 2) While the trait incidence in the whole Jomon series was 28.4%, an evident regional difference was found between the eastern Japan Jomon (18.1%) and the western Japan Jomon (33.1%-37.6%); 3) The difference in incidence between the Ainu (10.6%) and eastern Japan Jomon (18.1%), and that between the modern Japanese (37.4%)/Yayoi (33.7%) and western Japan Jomon (33.1%-37.6%) were not significant at the 5% level. From these findings, we inferred that the talar facet morphological variation of the calcaneus could be regarded as a trait deeply related to the diversity of the foot function due to different subsistence patterns, rather than one of the nonmetric traits under genetic control.
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  • A Study of Bone Compositions and Morphological Characteristics
    Soichiro Mizushima, Kazuhiro Sakaue, Gen Suwa
    2004 Volume 112 Issue 2 Pages 113-125
    Published: 2004
    Released on J-STAGE: December 24, 2004
    JOURNAL FREE ACCESS
    In order to discuss the characteristics and the significance of the "Banjo-shuseki" burials of the latest Jomon period, two assemblages of the Hobi shell mound, Aichi Prefecture, were investigated. These consisted of 87 (Shuseki-1) and 52 (Shuseki-B) human bone specimens. Element compositions, minimum number of individuals, and age representation of the Banjo-shuseki remains were determined. Sex composition was estimated from femurs, which were the most numerous element in each of the Banjo-shuseki burials. In determining sex, we constructed discriminant functions from femoral metric data of the individually buried human skeletons from the same Hobi site, for which reliable sex identification was possible from sufficiently preserved innominate bones. We then applied the functions to the Banjo-shuseki human femurs. We found that, in particular, femoral cortical area at midshaft was an excellent indicator of sex. Bone element compositions of the Hobi Banjo-shuseki burials were biased toward a higher representation of the lower limb bones. The number of individuals included was determined to be more than 14 in the Shuseki-1 burial (4 adult male, 6 adult female, 1 adult sex-unknown, 3 infant/juvenile) and more than 6 in the Shuseki-B burial (3 adult male, 2 adult female, 1 infant/juvenile). The morphological characteristics and mechanical robusticity of the Banjo-shuseki skeletal remains were compared with the condition seen in the individual burials from the same Hobi site. We focused on the femur, for which a sufficient number of specimens enabled statistical comparisons. In males, a significant difference was found in the pilasteric index between the Banjo-shuseki and individual burial remains, the former characterized by an extreme degree of pilaster development. Otherwise, in both sexes, significant differences were not found between burial types, either in femoral size or midshaft robusticity. The known bias in temporal and regional occurrences of the Banjo-shuseki burials and the elemental compositions and relatively large number of individuals represented in the Hobi examples of the present study suggest that these burials were based on intentional re-excavation and re-burial. Several explanations are possible for the prevalence of strongly pilasteric femurs in the Hobi Banjo-shuseki remains. One possibility is that the Banjo-shuseki burials might have been applied to a group of people with specific rank, activity role, or genealogical relationship.
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