Fig 5. Variation of the linear metrics in the European and African subsets.

(a) Scatterplot of sacral width (mm) and corpus width (mm); note the minimal overlap of females (red) and males (blue) in the European subset and the strong overlap in the African subset for corpus width. (b) Scatterplot of corpus depth (mm) and corpus width (mm) showing high correlation. (c) Fequency distribution of the corporo-basal index (CBI) and corpus-area index (CAI) for the complete sample. (d) Frequency distribution of the CBI and CAI for the European and the African subsamples; note the differences in the European (high discriminative power) and the African subsets (no discriminative power for CBI and moderate discriminative power for CAI).