Fluctuating odontometric asymmetry in the Lengua Indians of Paraguay.

Fluctuating dental asymmetry was evaluated as an indicator of environmental stress in a group of 202 living Lengua Indians from the Paraguayan Chaco area. Older, less accultured individuals were shown to be significantly more asymmetric than younger individuals who had been increasingly exposed to western foodstuffs and medicine. Lengua Indians demonstrated similar levels of asymmetry to another preliterate group, the Ticuna Indians of Columbia, but were found to be significantly more asymmetric than contemporary caucasoids. Similar patterns of asymmetry in both arcades for males and females were confirmed by analyses of variance and by Spearman's rank-order correlation coefficients. Partitioning variation in the degree of asymmetry by arcade, dimension and tooth revealed significant differences in the effects of tooth and arcade only: asymmetry was greater in the maxilla and greater in the more distal teeth within each morphogenic class.