台湾原住民 Paiwan 族の歯の形質人類学的研究

抄録

This paper describes the study performed in July 1979 to obtain the data on the tooth size and to investigate the morphologic characteristics of the tooth crown in the Paiwan tribe of the Taiwan aborigines. Hard plaster models were taken from 220 Paiwans inhabiting in a mountain area in Heito District, Taiwan. The author has conducted a comparison study between the Paiwan and the Japanese among other races, in particular, from the physical anthropological point of view. The results were as follows. 1. The data obtained show that the tooth size of the Paiwan tribe is little different from that of Japanese, the Ami and Atayal tribes, etc. but slightly smaller than that of the Ami and Atayal tribes and rather closer to that of the Japanese except for the labio-lingual diameter of the maxillary canine that is greater than that of the Japanese. 2. The frequency of occurrence of the double shovel-shaped incisors was found in 19.2% in male and 11.3% in female in the upper central incisors with very low frequency in other incisors. These data were compared with those of the Japanese and slightly less frequency was shown in the latter. The very high frequency of occurrence of the shovel-shaped incisor was found in 94.8% in male and 95.6% in female in the upper central incisors and in 85.9% in male and 81.7% in female in the lateral incisors, which were almost equal to those in the Ami and Atayal tribes and the inhabitants of Ishigaki Island but much higher than those for the Japanese in other parts. 3. The occlusal surface groove in the upper first premolar is of the basic A-type, in many cases, whereas that in the second premolar is of the more atrophic C-type, in many cases, showing the similar characteristics to those of the other Japanese, etc. 4. The occlusal surface pattern of the lower first premolar was mostly of E-type of the occlusal surface groove at the two cusp and the second premolar was mostly of the Types-A and -B at the three cusp. This is very similar to those of the inhabitants of Tanegashima and Ishigaki Islands but slightly different from those of the Kyushu inhabitants. 5. The very low degree of atrophy of the hypocone observed in the upper first molar was almost similar to that of the Ami and Atayal tribes. However, the degree of distinct atrophy of the hypocone in the second molar was lower than that of the Japanese. The mesiodistally compressed crown type, one of the forms of atrophy in the upper molars, was not observed in the first molar but often found in the second molar, which were higher in frequency of occurrence than that of the Japanese. The frequency of occurrence of the Carabelli cusp was 6.5% which is nearly equal to that of the Japanese and the Ami and Atayal tribes. 6. As to the occlusal surface morphology of the lower molar, 44.8% of the first molar was of the dryopithecus pattern of its basic type. This rate is less than that in the Japanese and the neighboring races. Especially, this pattern was hardly seen in the Ami and Atayal tribes of the Taiwan aborigines. From this point of view, this pattern may be considered as the characteristic physical morphology of the Taiyan aborigines. Namely, in the Paiwan tribe, the occlusal surface of the lower molar showed distinct atrophy of the groove pattern and little atrophy of the cusp. 7. The frequency of occurrence of the protostylid was 9.3% in the first molar which is approximately in the middle between those of the Ami and Atayal tribes and slightly less than that of the Japanese. The 6th cusp was observed in 23.3% of the first molar and 6.0% of the second molar, which are considerably less than those of the Hawaians and Polynesians showing little difference from those of the Japanese. The 7th cusp was observed in 7.4% of the first molar showing little difference from that of the Japanese. The deflecting wrinkle was observed only in the first molar with the frequency of occurrence of 53.4%, which

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