Résumé
Phylogenetic relationships between European cyprinids (Teleostei:Cypriniformes:Cyprinidae) were investigated by comparingcytochrome bgene sequences from 29 species, among which 20 were newly sequenced. Results were in general agreement with previous morphologically-based studies, but new interesting relationships were found. The classical barbelled/lacking barbels split is dubious. GenusLeuciscusappears paraphyletic. The phylogenetic location of some American cyprinid species was recovered; at least two distinct invasions of the New World are likely. Finally, the problem of intergeneric cyprinid hybrids is addressed. The genus rank for these interbreeding entities is supported and hybrids are seen as the consequence of a high genetic flexibility. This is the first molecularly based study of cyprinid diversity. It sheds light on the evolution and taxonomy of this major freshwater fish family.