Figure 2.

Distribution and sampling of Triturus macedonicus and T. karelinii and the zone of asymmetric introgression of T. karelinii mitochondrial DNA. Figure 2a shows the distribution of T. macedonicus (shaded green) and T. karelinii (blue). Note that the northwestern part of the range of T. karelinii is disconnected from the main range (i.e. it constitutes an enclave). Ranges are limited by sea (white), uninhabited land (grey) and other Triturus taxa (purple). Green dots represent T. macedonicus localities containing original T. macedonicus mitochondrial DNA, blue dots T. karelinii localities containing T. karelinii mitochondrial DNA, red dots T. macedonicus localities containing T. karelinii mitochondrial DNA and two orange stars T. macedonicus localities containing both original and introgressed mitochondrial DNA. Large dots represent localities for which mitochondrial DNA was sequenced and small dots additional localities included in ecological niche modeling. Localities where genetic admixture of the nuclear genome [based on allozyme data presented in Arntzen et al. submitted] is absent are denoted with a thick black border and those where at least one individual is present showing signs of nuclear genetic admixture are denoted with a thick grey border. Localities for which the composition of the nuclear genome could not be consulted were identified based on diagnostic morphological characters. Figure 2b shows the geographical distribution of mitochondrial DNA based on Thiessen polygons, where each polygon covers the area that is closer to its corresponding locality than to another one. Color codes are the same as in Figure 2a. The red and orange polygons were combined to delimit the zone of asymmetric mitochondrial DNA introgression.