Phylogenetic relationships among the delphinid cetaceans based on full cytochrome B sequences

Complete cytochrome b gene sequences from all bur one species of delphinid plus four outgroups were analyzed using parsimony, maximum likelihood, and neighbor-joining methods. The results indicate the need for systematic revi sion of the family; a provisional classification is presented and compared to previous studies. Among the suggested revisions are removal of Orcinus f rom the Globicephalinae, placement of Grampus within the Globicephalinae, r emoval of all Lagenorhynchus spp. from the Delphininae, and placement of So usa in the Delphininae. The genus Lagenorhynchus is found to be polyphyleti c. L. albirostris (type species for the genus) and L, acutus are. not close ly related to each other or to nominal congeners. L. acutus is therefore as signed to the genus Leucopleurus. The remaining four Lagenorhynchus species are closely related ro Lissodelphis and Cephalorhynchus and are placed in the genus Sagmatias. These three genera constitute the revised Lissodelphin inae. Within the Delphininae, a well-supported clade includes the two speci es of Delphinus, Stenella clymene, S, frontalis, S. coeruleoalba, and the a duncus form of Tursiops truncatus. Accepting the monophyly of this group re nders the genera Stenella and Tursiops polyphyletic. Apart from this findin g, phylogenetic resolution within the Delphininae was poor, so comprehensiv e taxonomic revision of this group awaits further study.