FIGURE 2. Measurements and canonical variates analysis (CVA) of the distal radius.

a, Illustration of the measurements collected in palmar and distal views. b, Bivariate plot of canonical scores, based on CVA of four shape measurements (DPI, NSI, SNA and SLA). Observed ranges of extant taxa (polygons), taxon means (crosses) and fossil specimens (circles) are shown. The two measures for AL 288-1 come from the left and right radii of this individual. c, UPGMA clustering diagram of the Mahalanobis D² distances among groups in multidimensional space (not limited to the axes shown in b). Note in b and c that the earliest hominid taxa A. anamensis (KNM-ER 20419) and A. afarensis (AL 288-1) exhibit the derived knuckle-walking morphology, whereas Paranthropus robustus (SKX 3602) and especially A. africanus (Stw 46) more closely resemble modern humans.