Phylogeographic analysis of the mitochondrial sequences of Galemys pyrenaicus . (A) Map of the northern part of the Iberian Peninsula showing the 134 samples of G. pyrenaicus used in this study. The grayed area represents the historical species distribution according to different sources. Names of mountain ranges mentioned in the text are shown. Each sample is represented by a circle, but a few samples with the same coordinates cannot be discerned. Colors of the samples indicate the four different mitochondrial lineages recovered in the phylogenetic analyses (A1, A2, B1 and B2). The single locality with two samples belonging to two different lineages (B1 and B2) is shown with both corresponding colors. The purple line indicates the genetic barrier identified by the Monmonier’s Maximum Difference algorithm (the intersection with the species distribution area is shown with stronger color). (B) Haplotype genealogy of the concatenated mitochondrial sequences based on a maximum-likelihood tree. Circles represent haplotypes, with size being proportional to the number of individuals, and black dots representing intermediate, unsampled haplotypes. (C) Bayesian tree of the same sequences. Posterior probabilities for relevant clades are shown. The scale bar represents 0.001 substitutions/position.