Abstract
Several phylogeographic studies using mtDNA sequence data have revealed an expressed geographic structure in nearly every European freshwater fish species studied. The authors present a phylogeographic study of Misgurnus fossilis on the base of 43 specimens from 17 localities across a major part of the known distribution area of M. fossilis . Despite the large geographic distance between the sampling points and their origin from different major European river systems, only eight closely related haplotypes in the sequences of the whole mitochondrial cytochrome b were detected. The most common haplotype I included more than 60% of specimens and occurred in the North Sea basin in northern Germany, in the Danube and Elbe basins in the Czech Republic, in the Nieman basin in Poland and in the Dniester and Vistula basins in the Ukraine. Since the highest number of haplotypes (six out of eight) and the most divergent haplotypes were found in the Danube, the authors tentatively consider the Danube to have acted as a refuge area for Misgurnus during the glaciation maxima in the Pleistocene. From this refuge, the species presumably recolonized Central and Eastern Europe but failed to stretch to Western Europe.