Abstract:The expressions of both sixth cusp (C6) and seventh cusp (C7) among the Malawians in East-Central Africa are described and compared with those of other African, Mongoloid, and Caucasoid populations.The subjects consisted of 99 males and 95 females. Scoring was performed using dental hard stone casts according to Turner's standard plaques. Asexual dimorphism in the occurrence of each trait was found to be not significant by chi-square test. The frequency of C6 in Malawians is remarkably lower than that in Mongoloid populations, and is located at the low range of frequency of C6 in the Caucasoid racial variation.On the other hand, C7 was observed more frequently in Malawian samples than in Mongoloid and Caucasoid populations. This tendency is in accordance with findings by Hellman on West AfricanNegroes and by Hanihara on Bantu and American Negroes.Therefore, it is likely that C7should be one of the components of the"Negroid dental complex". In general, the Malawians were similar to other African groups with the exception of the Teso in the occurrence of both traits. Concerning the frequency order between first and second lower molars in the Malawians, C6 and C7 appeared more often in first lower molars than in second lower molars. These results concerning C6 seriously question the validity of the"field concept"in relation to the human dentition.
The expression of the Bushman Canine dental trait among the Chewa tribe of East-Central Africa is described and compared with that of other African populations. Dental hard stone casts were obtained from 82 males and 76 females, and the trait was scored using the Arizona State University dental plaque system. No significant sexual dimorphism in the occurrence of the trait was found according to the chi-square test. The frequency of the Bushman Canine in the Chewa is markedly lower than that in a sample of San (Bushman) from Botswana. This helps support the view that the San represent either an ancestral or perhaps a different stock of people in comparison to other sub-Saharan Africans. When comparing the Chewa with a Central Sotho sample from South Africa, it appears that a gradient of the trait's frequency exists with decreasing expression from south to north. This gradient is probably caused by admixture between San and other peoples (mainly Bantuspeakers) who may not have originally possessed the trait. These findings agree with the so-called "Bantu-expansion" model proposed by several workers.
Abstract:The Carabeli complex on the maxillary first molars of Malawians residing in East-Central Africa and of Japanese was examined and classified according to the method of Alvesalo et al . with
The protostylid among the Malawians residing in East-Central Africa was examined and classified using Dahlberg's standard plaque. The occurrence of the protorstylid as an actual cusp was not found at all on first and second lower molars. This result is accordance with the finding on first lower molars in American Negroes. Therefore , the populationderived from Negroid racial stock seems to have less potentiality for expressing the protostylid than do other races. Hanihara mentioned that it might be better to be put the protostylid outside of the in the permanent dentition. However , taking into consideration the fact that Caucasoid-derived groups have a considerably lower frequency of the trait than do Mongoloid-derived groups , it is rather appropriate for the protostylid to beincluded as one component of the in the permanent dentition .
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