Fig 6. Principal components 1 and 2 of a PCA of symphyseal shape based on Fourier shape variables.

Shape differences (anterior facing left) associated with the PCs are illustrated below (PC 1) and to the left (PC 2) of the ordination. The samples include regionally appropriate modern humans, individuals with DS, Pleistocene Homo, Australopithecus and one Paranthropus boisei fossil, as well as LB1 and LB6. LB1 and LB6 are quite similar in their symphyseal shape and most closely resemble A. afarensis. The DS sample overlaps the euploid modern humans and some Pleistocene Homo samples. The first two components accounted for 73.1% and 9.6% of the total variance, respectively (PC 1 eigenvalue = 0.01; PC 2 eigenvalue = 0.001).