First look into the evolutionary history, phylogeographic and population genetic structure of the Danube barbel in Croatia

Abstract

The Danube barbel, Barbus balcanicus is small rheophilic freshwater fish, belonging to the genus Barbus which includes 23 species native to Europe. In Croatian watercourses, three members of the genus Barbus are found, B. balcanicus, B. barbus and B. plebejus, each occupying a specific ecological niche. This study examined cytochrome b (cyt b), a common genetic marker used to describe the structure and origin of fish populations to perform a phylogenetic reconstruction of the Danube barbel. Two methods of phylogenetic inference were used: maximum parsimony (MP) and maximum likelihood (ML), which yielded well supported trees of similar topology. The Median joining network (MJ) was generated and corroborated to show the divergence of three lineages of Barbus balcanicus on the Balkan Peninsula: Croatian, Serbian and Macedonian lineages that separated at the beginning of the Pleistocene. Croatian lineage of B. balcanicus shows a uniform structure with many recently diverged haplotypes, which was further supported by the star-like shape of the MJ network. Effective size estimates were obtained for populations inhabiting separate river catchments and the results imply the good reproductive potential of Barbus balcanicus in Croatia, which is in positive correlation with the overall high genetic diversity calculated for its populations. Nevertheless, population sizes of several population seem to be reduced as a consequence of habitat degradation and fragmentation.

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

“…barbus obtained throughout its distribution range (Kotlik & Berrebi, 2001), whereas an investigation of B . balcanicus in Croatia revealed 15 haplotypes in 115 samples (Raguž et al, 2021).…”

“…When comparing genetic structure and diversity observed in Aulopyge with reports on phylogenetically more closely related species (belonging to the genus Barbus), these differences are less pronounced. For example, 11 haplotypes were discovered in 87 samples of B. barbus obtained throughout its distribution range (Kotlik & Berrebi, 2001), whereas an investigation of B. balcanicus in Croatia revealed 15 haplotypes in 115 samples (Raguž et al, 2021). Stroil et al, 2019;Ludoški et al, 2020).…”

Tackling the Phylogeny of Lampreys—Insight from the Croatia’s Danube Basin

“…Dnieper, has already been observed as an important period in the evolutionary history of the fish species distributed in the Danube River basin. The first major diversification event within the genus Barbus was also associated with this period [5]. Since the Proto-Danube progressed slowly, reaching the Vienna basin at 14-13 mya and the Pannonian basin at 10-5 mya [39], it is possible that the evolutionary history of both E. danfordi and E. vladykovi was largely shaped by the evolution of the Danube River basin, especially since 10-5 mya is the exact time frame when the origin of E. vladykovi lineages and the origin of diversification of the Croatian E. danfordi population occurred.…”

“…These events, coupled with the effects of glacial and interglacial periods, have facilitated the creation of harbors for fish populations during glacial periods and their subsequent dispersal to rivers in central and northern Europe after the last glaciation [1]. With its distinctive geomorphological and hydrological features, the Danube basin and its tributaries are emerging as a hotspot of European ichthyofaunal diversity, housing an impressive 81 species of freshwater fish species (64 native and 17 invasive species) [2][3][4][5].…”