Abstract
The Central-Southern European genus Besdolus was reinstated and revised by Zwick and Weinzierl (1995), and includes five species: B. imhofft (Pictet), B. ventralis (Pictet), B. bicolor (Navas), B. ravizzarum Zwick & Weinzierl, and B. illyricus Kovacs& Zwick. Overall, these species are rarely collected and have apparent relictual distributions. From the ecological point of view, B. bicolor, B. ravizzarum and B. illyricus seem to be more orophilic whereas B. imhofft and B. ventralis are associated tolowland rivers. These species are sensitive to the environmental perturbations and are endangered taxa, threatened with extinction. Species identifications are difficult using available morphological characters. We sequenced a fragment of the mitochondrial gene COI to better understand the systematics and biogeography of this genus and to evaluate the molecular intra- and interspecific distances. Specific boundaries, species relationships, degree of isolation and molecular similarity are also presented.The molecular data do not fully support the validity of the five species. Molecular distances between B. bicolor and B. ventralis and between B. imhofft and B. illyricus are similar to what has been previously reported for conspecific stonefly taxa. Inthis study, the results of the molecular approach are not congruent with the traditional morphological arrangement. Biogeographically, we hypothesize that a Central European stem species dispersing westward and southward diverged into two lineages, thendifferentiated on the three European main peninsulas.
NSTL