a) MtDNA haplotype phylogeny. Midpoint-rooted Bayesian 50% majority-rule consensus tree with posterior probabilities above 0.5 indicated above branches. The scale bar refers to branch lengths (expected changes per site). Median-Joining networks for P. sundbergi (b) and P. astriata (c). Islands are colour-coded and circle size is proportional to the number of individuals. Full grey dots along branches represent missing or unsampled haplotypes. Islands labelling is as follows: Aride (ARD), Curieuse (CUR), Grande Soeur (BS), Praslin (PL), La Digue (LD), Cousine (CNE), Fregate (FG), Cerf (CF), Mahé (MA), Silhouette (SILH) and North (NOR). Highlighted haplotypes (***) correspond to the individuals from Mahé and La Digue found to cluster within P. sundbergi sundbergi (from Curieuse and Praslin) (see text). The outer islands of Cosmoledo, Astove (AT), Poivre and Alphonse (APH) are identically coloured in white (see Results for detailed information).