Acknowledgements Prologue 1. Dental anthropology and morphology 2. Description and classification of permanent crown and root traits 3. Biological considerations: ontogeny, asymmetry, sex dimorphism and intertrait association 4. Genetics of morphological trait expression 5. Geographic variation in toot crown and root morphology 6. Establishing method and theory for using tooth morphology in reconstructions of late Pleistocene and Holocene human population history 7. Tooth morphology and population history Epilogue Appendices References Index.

The Anthropology of Modern Human Teeth: Dental Morphology and its Variation in Recent Human Populations

この論文は, 沖縄人およびアイヌを含む日本人集団の形成史を単一の仮説で説明する二重構造モデルを提唱するものである。このモデルは次の点を想定する。すなわち, 日本列島の最初の居住者は後期旧石器時代に移動してきた東南アジア系の集団で, 縄文人はその子孫である。弥生時代になって第2の移動の波が北アジアから押し寄せたため, これら2系統の集団は列島内で徐々に混血した。この混血の過程は現在も続いており, 日本人集団の二重構造性は今もなお解消されていない。したがって身体•文化の両面にみられる日本の地域性-たとえば東西日本の差など-は, 混血または文化の混合の程度が地域によって異なるために生じたと説明することができる。またこのモデルは, 日本人の形質•文化にみられるさまざまな現象を説明するのみならず, イヌやハツカネズミなど, 人間以外の動物を対象とする研究結果にも適合する。同時に, このモデルによって日本の本土, 沖縄およびアイヌ系各集団の系統関係も矛盾なく説明することができる。

https://www.jstage.jst.go.jp/article/ase1993/102/5/102_5_455/_pdf

Dual structure model for the population history of the Japanese

The study of modern human origins and the study of the origins of modern human diversity are intimately linked. The evolutionary models employed have implications both for interpreting the significance of morphological variation and evolutionary trends, and in terms of the processes that gave rise to such variation. Although controversial, available evidence is taken to indicate a single, recent origin of modern humans.



This paper explores the process of differentiation of modern populations in Asia and argues for morphological discontinuities in the late Pleistocene populations in the region. The intensely studied population history of Eastern Asia suggests that the evolution of the Mongoloid population complex may result from a process of differentiations, expansions, and dispersals, resulting in the development of regional morphological patterns. The relatively late appearance of regional morphological differentiation, especially in Northeast Asia, opens the possibility of the earliest Amerindians not being a typical “Mongoloid” population.



A more generalized Mongoloid morphology has been described for both North and South American Paleoindian remains. In this paper, the morphology of a robust, not typically Mongoloid, population in South America is investigated, and its implications for the homogeneity of Amerindians discussed. Since a derived, typically Mongoloid morphology cannot be attributed to the early Amerindian and Fueguian-Patagonian populations, it is argued either that the sinodont dental pattern was acquired in parallel in Asia and the Americas or that at least two migratory waves ancestral to Amerinds took place. © 1995 Wiley-Liss, Inc.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/ajpa.1330380609

Patterns of modern human diversification: Implications for Amerindian origins

Identification of sex from the skeleton is an important demographic assessment in medicolegal investigations. Studies have demonstrated that populations differ from each other in size and proportions and that these differences can affect the metric assessment of sex. It is therefore vital to determine if population differences are great enough to necessitate group-specific standards. To date, there have been no attempts to create standards of assessment for modern Thais. Therefore the purpose of this research is to establish standards from which to determine sex from the femur using a new skeletal collection housed at the Chiang Mai University Department of Anatomy. The sample is composed of 104 individuals (70 males, 34 females). Six standard osteometric dimensions including maximum length, maximum head diameter, midshaft circumference, midshaft anterior-posterior and transverse diameters, and bicondylar breadth were measured and analyzed by stepwise discriminant function statistics. To understand population differences, formulas derived from Chinese, South African whites and American whites and blacks using the same method and variables were tested on the Thai sample. Results indicated that maximum head diameter and bicondylar breadth are the optimal combination for sex diagnosis and yielded 94.2% accuracy. Direct analysis using predetermined single or multiple variables also revealed bicondylar breadth as the best single dimension (93.3%). In cross-tests on the Thais, the Chinese formula gave the most favorable outcome with unsatisfactory results for all other groups. The present research confirms that sexual dimorphism is better reflected in breadth dimensions than in bone length. Comparisons showed that Thais are very different metrically from whites and blacks, and although they most resemble the Chinese, these two groups are not identical. These findings underscore the need for population-specific formulas for identification of sex from the skeleton.

Metric and Comparative Analysis of Sexual Dimorphism in the Thai Femur

Sexual dimorphism in the humerus: a comparative analysis of Chinese, Japanese and Thais.

Morphological patterns of similarity and difference derived from an assessment of metric and non-metric dental characters in a series of Jomonese and their lineage in Japan, Southeast Asians, Micronesians, and Polynesians were presented. Despite the marked difference of phenotypic features, the dentitions of Negritos, Dajaks, and Filipinos show close resemblance to each other. The original dental traits of Southeast Asians may have occurred by the result of convergent microevolution under the similar environmental condition such as tropical rain-forest. Diachronic comparison of Southeast Asian dental samples supports the local evolution hypothesis for modern Southeast Asian dental characters. Dental traits of Micronesians and Polynesians are more like those of Southeast Asians than those of Jomonese and their lineage. The present findings do not favor the Neolithic Jomonese as the most likely source for the present people in Micronesia and Polynesia. Jomonese may be linked with the Pacific populations through the common gene pool derived from somewhere in Southeast Asia.

https://www.jstage.jst.go.jp/article/ase1911/100/1/100_1_53/_pdf

Biological Relationships among Southeast Asians, Jomonese, and the Pacific Populations as Viewed from Dental Characters: The Basic Populations in East Asia, X

The dental features of 4 geographical samples from the Nansei Island chain were compared with those of East and Southeast Asian samples. The series from Amami-, Okinawa-, and Sakishima-Islands exhibit inter-regional difference in both metric and non-metric dental features, pointing to some clinal variation in the Nansei Island chain. The original morphology is supposed to be represented by Jomonese. This clinal variation may reflect the post-Yayoi biocultural microevolution and admixture with the sinodont populations from main-island Japan. The sundadont ancestors of Jomonese have likely arrived from Sundaland via the now-submerged East Asian continental shelf in and after the late Pleistocene. One of the main routes for peopling of the Japanese Archipelago might have been through the Nansei Island chain.

Dentition of Nansei Islanders and Peopling of the Japanese Archipelago: The Basic Populations in East Asia, IX

Dental characteristics of Aeta, one of the Negrito tribes in westcentral Luzon, the Philippines, were compared with those of Japanese, Ainu, PimaIndians, Australian Aborigines, Filipinos, American Caucasoids and American Blacks. The overall tooth size of Negritos is smallest among the populations compared and closest to Ainu. As regards the shape factor of the dental measurements, they are closely related to Mongoloid populations as revealed by Q-mode correlation coefficients. These findings are almost parallel to the results obtained by principal component analysis. On the other hand, Bsquare distances based on seven non-metric crown characters show close affinity between Negritos and Ainu. The frequency distribution of the crown characters in both populations well corresponds to the "Sundadont" pattern defined by TURNER (1987).The results obtained from the present study, together with TURNER'S (1978, 1979, 1987, 1989) dental anthropological model of the late Pleistocene population history in southeast Asia, support the hypothesis proposed by OMOTO (1984, 1986) who suggested that Negritos might have shared an ancestral stock with Semang of Malaysia and evolved in the upper Pleistocene times under the environment of tropical rain-forest in Sundaland.

Affinities of the Philippine Negritos as Viewed from Dental Characters: A Preliminary Report

In recent years, considerable attention has been paid on the physical characteristics of the Ainu and the Okinawa Islanders in connection with the origin of modern Japanese. In the present study, the metric traits of the dentition in the Tokunoshima Islanders, the Aogashima Islanders, the Okinawa Islanders and the Ainu were compared with each other and with those in the modern populations from Tokyo and Nagasaki, and the Aeneolithic Yayoi population. The first four populations have been isolated or at least nearly isolated for a long period from the populations of main island of Japan because of their geographic conditions.As regards the shape factors in the dentition, the four isolated populations are closely related to each other, and they show closer affinities to the Tokyo population than to the Nagasaki and the Yayoi populations. The shape factor in the latter two populations shows similar trends but is quite different from that in the other four isolated populations as well as the Tokyo population. Using the principal component analysis method, it is elucidated that the relative size of premolars and incisors plays an important role in difference of the shape factor among the populations. Taking all the results obtained into account, the characteristics of the dentition in the isolated populations are likely under the same genetic control which is common to the Neolithic Jomon population. The origin and affinity of modern Japanese are discussed on the basis of such findings.

Comparative Studies of Geographically Isolated Populations in Japan Based on Dental Measurements

This paper is concerned with the problem of the origin and the racial affiliation of recent Sakhalin Ainu, rather than with the well-known uniqueness of the cranial morphology of this population. In this study, odontometric and morphological observations were performed on the dentition of Sakhalin Ainu.The overall tooth size of Sakhalin Ainu is quite small. In this respect, Sakhalin Ainu shares the similar characteristics with those of Hokkaido Ainu, the Neolithic Jomon population, some geographically isolated Japanese, and Negritos. As regards the shape factor of the dental measurements, on the other hand, Sakhalin Ainu shows the close affiliation to the typical Mongoloid populations such as Aleuts, Karluk (Alaska Eskimos), Chinese from the northern area of China and modern main island Japanese. Distance analysis based on the several non-metric crown features displays the intimate association of Sakhalin Ainu with Negritos and the populations who may have been derived directly from Southeast Asian Proto-Mongoloid population.Taking these results into account, we cannot ignore some genetic influence of Northeast Asian populations on the physical characteristics of Sakhalin Ainu. However, the origin of this population may have been traced back to the Southeast Asian Proto-Mongoloid population. The dental evidence shown in this study may contribute to the establishment of biological relationships among Sakhalin Ainu and the neighboring populations.

Tsunehiko Hanihara

Papers

Biological Relationships among Southeast Asians, Jomonese, and the Pacific Populations as Viewed from Dental Characters: The Basic Populations in East Asia, X

Dentition of Nansei Islanders and Peopling of the Japanese Archipelago: The Basic Populations in East Asia, IX

Affinities of the Philippine Negritos as Viewed from Dental Characters: A Preliminary Report

Comparative Studies of Geographically Isolated Populations in Japan Based on Dental Measurements

Studies on the Affinities of Sakhalin Ainu Based on Dental Characters: The Basic Populations in East Asia, III