Evolutionary history of the Balkan endemic genus Delminichthys (Teleostei, Leuciscidae) with an emphasis on the population structure of Southern Dalmatian minnow

Abstract

The genus Delminichthys consists of allopatric species restricted to ephemeral watercourses in the karst fields of the left-bank (D. ghetaldii) and the right-bank (D. adspersus and D. jadovensis) Neretva River basin as well as in the Una River drainage (D. krbavensis). The first aim addressed questions of interspecies variation and phylogenetic relationships among Delminichthys based on time-calibrated analysis of cyt b mtDNA (cytochrome b) and COI mtDNA (cytochrome c subunit I) mitochondrial DNA genes. Species-specific haplogroups supported two mtDNA genes as suitable barcoding markers, while we additionally proposed character-based and genetic distance threshold-based delimitation of species. We confirmed that the Pliocene and Pleistocene refugium for freshwater species was the Neretva basin, promoting the diversification of the genus Delminichthys. Our second aim was to test the population structure of D. ghetaldii (Southern Dalmatian minnow) by performing an integrative study using molecular mtDNA data, linear and geometric morphometric data. We consider that the spatial aspects of the population genealogical structure of D. ghetaldii mirror the Pleistocene paleodrainages. The differentiated COI mtDNA clusters corresponding to the populations from Fatničko Polje+Dabarsko Polje and Ljubomirsko Polje+Konavosko Polje represent geographically discrete genetic entities, which should be addressed through conservation management.