Molecular phylogeny of Palearctic-African Acrocephalus and Hippolais warblers (Aves : Sylviidae)

Phylogenetic relationships of the reed warbler group (genera Acrocephalus, Hippolais, Chloropeta; Aves: Passeriformes) and their potential relatives w ere studied using nucleotide sequences (1 kb) of the mitochondrial cytochro me b gene. This species-rich but morphologically poorly differentiated grou p of insectivorous passerines is distributed in Eurasia, Africa, and Austra lasia. Intergeneric relationships were poorly resolved, but monophyly of th e reed warbler group (including Chloropeta) versus other Sylviidae was stro ngly supported. A basal polytomy within the reed warbler group consists of seven branches and may indicate a rapid early radiation. In the genus Acroc ephalus three major clades were identified, which corresponded to phenotypi c groups characterized by body size and plumage patterns. However, current delimitation of some subgenera (Acrocephalus, Lusciniola, Bebrornis) is at variance with our phylogeny estimate, and appropriate revisions are propose d. The genus Hippolais, which may or may not be monophyletic, consisted of two well-supported clades of four species each. Some Acrocephalus taxa whos e species status had been doubted (griseldis, tangorum, orientalis, austral is) proved to be highly distinct genetically. Genetic distances between mem bers of two pairs of allopatric Hippolais taxa (caligata/rama; opaca/elaeic a) were as large or larger than between other closely related warbler speci es. Overall, cytochrome b sequences resolved phylogenetically young relatio nships quite well, whereas more ancient nodes remained poorly resolved. (C) 1999 Academic Press.