Cryptic diversity in Telestes pleurobipunctatus (Actinopterygii; Leuciscidae) as a consequence of historical biogeography in the Ionian Freshwater Ecoregion (Greece, Albania)

It was reported that the complex geological history of the southern Balkans caused diversification of terrestrial species. On the other hand, knowledge of the evolutionary history of freshwater biota is scarce. In order to contribute to an understanding of the historical biogeography of the region's freshwaters, as well as to describe intraspecific diversity and structure of a species distributed in the Ionian Ecoregion, we have analysed the population genetic structure and evolutionary history of Telestes pleurobipunctatus. Analyses were based on the mitochondrial gene for cytochrome b from samples covering the whole distribution range of this species. A high level of intraspecific structuring was revealed inside T. pleurobipunctatus. Its evolutionary history corroborates the complexity of historical geologic events in the area. Telestes pleurobipunctatus comprises two main clades (northern and southern), which have been separated from each other for about seven million years and that are further divided. The Louros and Arachthos Rivers were denoted as ancestral geographic ranges of the northern clade. The distribution range of the ancestor of the southern clade seems to comprise rivers flowing into the Patraikos Gulf. Structures within the two main clades, as well as timing of diversification events are different, implying separate evolutionary courses.