Sampling localities (A–J) from which specimens of Nassarius kraussianus were collected. The sample sizes were: A = 350, B = 104, C = 132, D = 112, E = 47, F = 183, G = 83, H = 54, I = 71, J = 94. Blue circles indicate localities dominated by haplotypes present in the western range of the species' distribution, and red circles indicate sites where haplotypes of the eastern lineage were mostly found. The location of Blombos Cave (where N. kraussianus fossils were found that were worn as beads by human beings during the Middle and Late Stone Age) is indicated.