Face Shape Differences in Selected Indigenous Peoples’ Groups in Mindanao, Philippines

Abstract

The face shape of individuals belonging to seven different indigenous groups (IG) from Mindanao was studied using geometric morphometric analysis. A total of 496 images of the face (217 males and 279 females) were obtained from the Bagobo, Bilaan, Higaunon, Kalagan, Maranao, Subanen and Talaandig groups. Forty three manually defined landmarks done in triplicates generated relative warp scores which were subjected to different statistical tools in order to compare face shapes and to examine relatedness between IGs. Non-metric multidimensional scaling and discriminant analysis showed significant variation between IGs however, patterns of clustering were different in male and female populations. Procrustes ANOVA showed that sides, individual, and interaction in all IGs of both populations had P-values of <0.000, which is indicative of the presence of asymmetry, distinctness of the face shape each individual, and a significant variation among IGs in both male and female populations. The interaction of sides and individual p-value showed high fluctuating asymmetry (FA) for all IGs regardless of gender. This may be attributed to the intermarriage practices between individuals of same IG which are still applicable to some groups nowadays. In conclusion, each IG possesses distinct face shape but individuals belonging to each group have high degree of variation.