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

Systematics of the European species of the genus Barbus is controversial for decades because of the relative similarity in general morphology between species. The use of more objective and precise characters, such as osteology, has given improved results. However, in the absence of a thorough morphological analysis of the group, genetic markers providing a promising method for obtaining more accurate phylogenies.On the basis of distinct ecological and morphological characters, the European Barbus taxa have been clustered in two groups : a fluvio-lacustrineand a rheophilic or strictly riverine one. These two groups (or ecophenotypes) were recognised in different parts of Europe, and formed, either a species assemblage (Barbus barbus group) or a polytypic species (Barbus meridionalis). The implicit idea is that species of to the same group belong, to the same phylogenetic lineage (clade) and are the result of the same transcontinental colonisation event.The analysis, using allozyme markers, of 10 taxa of the genus Barbus from France, Italy, Greece, the Czech Republic and Slovakia, showed that the taxa thought to belong to the fluvio-lacustrine and the rheophilic groups are not monophyletic. We mention some alternative hypotheses, including the possibility that the allozyme markers may be inadequate. The results suggest that probably in each sub-region, the founding taxon has diverged independently to form species of two different ecophenotypes ; one occupying the upstream rivers and another found in the lowland rivers. Accordingly, Barbus species groups represent clusters of morphologically convergent taxa living in equivalent biotopes