Phylogeographic pattern, genetic diversity, and evolutionary history of the enigmatic freshwater fish species Aulopyge huegelii (Actinopterygii: Cyprinidae)

The genus Aulopyge, represented by a single species, the Dalmatian barbelgudgeon, Aulopyge huegelii, is an endemic genus with very restricted distribution range comprising several rivers in southern Croatia and Bosnia and Herzegovina. In this study, molecular genetic analyses based on three molecular markers (one nuclear and two mitochondrial) were performed to confirm the position of Aulopyge within Cyprinidae, obtain data on its evolutionary history, and describe its population genetic structure and diversity. Specimens of A. huegelii were obtained throughout the distribution range. Phylogenetic reconstruction corroborated the independent position of this species and its placement within the Barbinae subfamily. The evolutionary history of A. huegelii started already in the middle Oligocene, whereas intraspecific divergences that left a trace in its current genetic structure and diversity are of much younger origin, starting in the middle Pleistocene. Unlike in other cypriniform species and genera distributed in the Dinaric karst region, there is no significant structuring within A. huegelii, or distribution of haplotypes concordant with the geographic scale. Furthermore, low effective population sizes estimated for most populations and low genetic diversities within them raise strong concerns about the viability and future survival of this endemic species.