Integrative study of population structure of Telestes dabar, the strictly endemic cyprinid species from the Dinaric karst on the Balkan Peninsula

Diversification of the genus Telestes (Cyprinidae), endemic to the Euro-Mediterranean biogeographic subregion, mirrored an evolutionary footprint of complex biogeographical history. Hence, hidden diversity and noticeably high endemicity of freshwater ichthyofauna were discovered in the Dinaric karst on the Balkan Peninsula. One such example includes two steno-endemic Dinaric karst (Bosnia and Herzegovina) cyprinid species, Telestes dabar and T. metohiensis. Although the conservation status of T. metohiensis has been evaluated, T. dabar from Dabarsko Polje has not yet been assessed for the IUCN Red List due to its taxonomically ambiguous position and data deficiencies. Our first aim was to evaluate the resolution of taxonomic ambiguities of the two putative species, T. dabar and T. metohiensis, by the complementary use of two mitochondrial DNA markers (cytb and COI mtDNA). The results clearly demonstrated the evolutionary independence of T. dabar (Dabarsko Polje) and T. metohiensis (Nevesinjsko Polje) and confirmed the usefulness of both markers for assessing the species borders. In addition, population structure of putative T. dabar was analyzed using cytb and COI mtDNA and morphological parameters (linear measurements and landmark-based geometric morphometric data). A high genetic admixture and homogeneity in T. dabar from Dabarsko Polje were found and confirmed using both morphometric approaches as no statistically significant differences were consistently registered between different samples.