The North Mediterranean Barbus lineage: phylogenetic hypotheses and taxonomic implications based on allozyme data

On the basis of distinct ecological and morphological characters, the Europ ean Barbus taxa have been clustered in two groups: a fluvio-lacustrine and a rheophilic or strictly riverine one. These two groups (or ecophenotypes) were recognized in different parts of Europe, and formed either a species a ssemblage (Barbus barbus group) or a polytypic species (Barbus meridionalis ). The hypothesis was that species of the same group belong to the same phy logenetic lineage (clade) and are the result of the same transcontinental c olonization event. The analysis, using allozyme markers, of 10 taxa of the genus Barbus from France, Italy, Greece, the Czech Republic and Slovakia, s howed that the taxa thought to belong to the fluvio-lacustrine and the rheo philic groups are not monophyletic. The results suggest that probably in ea ch sub-region, the founding taxon has diverged independently to form specie s of two different ecophenotypes, one occupying the upstream rivers and the other the lowland rivers. Accordingly, Barbus species groups represent clu sters of morphologically convergent taxa living in equivalent biotopes. (C) 1999 The Fisheries Society of the British Isles.