Morphological and Molecular Differentiation between Rheophilic Barbels Barbus spp. (Cyprinidae) from Headwaters at the Divide between Drainage Areas of the Danube, Vardar and Struma Rivers, Central Balkans

Abstract

External morphology and cytochrome b structure of rheophilic barbels from headwaters of the Pčinja, Vrla (Barbus balcanicus) and Dragovištica (B. strumicae) Rivers in Southern Serbia at the watershed between the drainage areas of the Vardar (Axios), Danube and Struma (Strymon) Rivers, respectively, were examined. Barbel specimens from the Pčinja River were clearly different from both congeners from the other two rivers in the shape of the head and the length of the caudal fin. They were closer in external morphology to B. strumicae from the Dragovištica River as compared to B. balcanicus from the Vrla River. On the contrary, their relationship inferred from the structure of cytohrome b revealed closer relationshipbetween B. balcanicus and the rheophilic barbel from the Pčinja River. Despite of the differentiation inmorphology found between specimens of the rheophilic barbel, the divergence between them was insufficientfor sound taxonomic inferences. Their phylogenetic relationships shed some new light on theirevolutionary history in the study area.