Vicariance, colonisation, and fast local speciation in Asia Minor and the Balkans as revealed from the phylogeny of spined loaches (Osteichthyes; Cobitidae)

We reconstruct the phylogeny of the morphologically diagnosable subgenera Bicanestrinia, Beysehiria, and Cobitis sensu stricto of the genus Cobitis from Asia Minor and the Balkans. We used the complete cytochrome b gene of 65 specimens in order to infer their evolutionary history in this zoogeographically interesting area. Our phylogeographic analysis did not evidence the previously suggested monophyly of the Bicanestrinia subgenus but revealed five monophyletic lineages in the area: the lineages Bicanestrinia I-IV including all species of Bicanestrinia plus the lineage Cobitis s. str. The monotypic subgenus Beysehiria from Lake Beysehir in Anatolia was closely related to the syntopic population of C. turcica and nested inside the lineage Bicanestrinia III. The strictly allopatric distribution of the four lineages of Bicanestrinia suggests that vicariance has played a major role in the diversification of Bicanestrinia. All analysed species of Cobitis s. str. from Asia Minor and Balkans were closely related to Cobitis s. str. from Central Europe, the Danube basin and the Caucasus, indicating at least two colonisation events into Asia Minor and the Balkans. A third, recent colonisation event led to the presence of C. strumicae, generally restricted to the Aegean Sea drainage, in the Danube basin. Besides the evidences of vicariance and colonisation events in the phylogenetic history of the genus Cobitis in Asia Minor and the Balkans, our analysis suggested also a rapid morphological evolution of C. bilseli in a lacustrine environment. Application of Cobitis mitochondrial cytochrome b clocks of 0.68% sequence divergence per million years (MY) suggest that the split between the five major lineages happened approximately 12.4-17.6 MYA, and according to the lack of basal resolution of this monophyletic group probably the split of all lineages happened within a narrow time window.