Variability of colour pattern and genetic diversity of Salamandra salamandra (Caudata: Salamandridae) in the Czech Republic

Abstract

Two evolutionary lineages of the fire salamander occur in central Europe: the typically striped subspecies Salamandra salamandra terrestris (Bonnaterre, 1789) and the typically spotted Salamandra salamandra salamandra (Linnaeus, 1758). In the Czech Republic, fire salamanders have traditionally been viewed as belonging to the S. s. salamandra evolutionary lineage. Nevertheless, the colour pattern of some individuals in the westernmost part of the Czech Republic resembles that of S. s. terrestris in having parallel continuous bands along the back. In this study, we investigated whether in the Czech Republic the presence of striped fire salamander phenotype could be associated with the genotype of S. s. terrestris. We sequenced the mitochondrial D-loop and two nuclear markers, Rag2 and PDGFRα, of 61 fire salamander individuals from the Czech Republic. To describe the geographical distribution pattern of the striped and spotted fire salamander phenotype in the Czech Republic, we evaluated colour phenotypes of 398 individuals from ten localities distributed so as to cover the whole country. We found no evidence of presence of genotypes corresponding to the S. s. terrestris lineage. We did, however, find that the striped phenotype is found mostly in the northwest of the Czech Republic, where both the striped and the intermediate phenotype occur significantly more frequently than in the rest of the country, where the spotted phenotype seems dominant. This finding indicates that Czech and Polish populations of S. salamandra show a degree of phenotypic pattern variation comparable to that observed in German populations, although at a local level the frequencies of the striped and spotted phenotype vary. It would be interesting to test whether a genetic toolkit responsible for the colour pattern is shared via genetic introgression between populations, or whether the striped phenotype of Czech fire salamanders evolved independently.