Two new species of stone loaches of the genus Barbatula (Cypriniformes: Nemacheilidae) from Europe with a neotype designation of B. barbatula (Teleostei: Nemacheilidae)

Ten species of Barbatula are recognised in Europe, west of the Urals: B. barbatula, B. caucasica, B. hispanica, B. leoparda, B. pironae, B. quignardi, B. sturanyi, B. taurica, B. vardarensis and B. zetensis, with B. caucasica and B. taurica formerly considered subspecies of B. barbatula. A comprehensive dataset of the DNA barcoding gene coI recovered four major clades within Europe: three in Eastern Europe including B. caucasica, B. pironae, B. sturanyi, B. taurica, B. vardarensis and B. zetensis, and one in Western Europe including B. barbatula, B. hispanica and B. leoparda.

The results further indicated several genetic lineages, representing potentially new species. Recent surveys in Switzerland revealed two new species of Barbatula, within the Western clade, which are herein described. Barbatula fluvicola, a new species, inhabits streams and rivers in the upper and middle Rhine drainage in Switzerland and Germany, as well as the upper Danube drainage in Germany and Austria.

Barbatula ommata, a new species, is mostly confined to lakes of the Aare-Rhine system. The two new species overlap geographically in Switzerland, where they occupy different habitats. Morphological differences, species delimitation analyses, phylogenetic reconstruction and genetic distances based on the coI gene corroborates the recognition of the two new species.

To stabilise the nomenclatural status and the consequent use of the nomen B. barbatula, we are herein designating an unambiguously identifiable neotype from the Lez River population, previously recognised as B. quignardi, to clarify the identity of the nominal species Cobitis barbatula Linnaeus, 1758. K E Y W O R D S biodiversity, Danube River, European fishes, freshwater, lakes, Rhine River, systematics