Study area and genetic results. A) Map of the study area and sampling sites. Black dots: localities either mentioned in the text or used for ecologic data; blue dots: localities used for genetic data abbreviated as in Table 1. Continuous, black line: distribution of the western lineage (according to ); dashed, black line: distribution of the eastern lineage (according to ). The three biogeographic regions of southern Africa (according to ) are delimited by grey dotted lines. B) Results of the Bayesian approach using the Discriminant Analysis of Principal Components (DAPC) scatter plot of individuals with a priori-defined locations, to investigate genetic structure. Labels were placed at the centre of dispersion of each group, which are delineated by inertia ellipses. C) DAPC a posteriori genetic cluster assignment for K = 2. The size of each square is proportional to the percentage of individuals assigned to each cluster at each location. D) Stacked bar graph of assignment probabilities per individual within P. perna locations across the southern tip of South Africa. Assignment proportions for each individual were obtained from Structure, based on genotypes from seven nuclear microsatellite loci, for K = 2.