Evolutionary relationships among extant albatrosses (Procellariiformes: Diomedeidae) established from complete cytochrome-b gene sequences

Abstract

Complete mitochondrial cytochrome-b gene sequences (1,143 bp) were determined from the 14 extant species in the Diomedeidae (albatrosses and mollymawks) and in two outgroup species from the Procellariidae (petrels and shearwaters). Phylogenetic analysis using maximum parsimony and maximum likelihood methods identified a single best-supported hypothesis of evolutionary relationships within the Diomedeidae, namely that two lineages arose early in the evolution of the Diomedeidae. A further bifurcation in each of these lineages resulted in four monophyletic groups of albatrosses: (1) southern mollymawks, (2) sooty albatrosses, (3) North Pacific albatrosses, and (4) "great" albatrosses. Monophyly of the southern mollymawks (Diomedea bulleri, D. cauta, D. chlororhynchos, D. chrysostama, and D. melanophris) and sooty albatrosses (Phoebetria fusca and P. palpebrata) indicates that Diomedea is paraphyletic. Resurrection of two genera, dropped historically in taxonomy of the Diomedeidae, results in a total of four genera. Calibrations based on the fossil record indicate that cytochrome-b evolutionary rates in albatrosses are slow compared with those of most mammals.