Phylogenetic differentiation of Sylvia species (Aves: Passeriformes) of the Atlantic islands (Macaronesia) based on mitochondrial DNA sequence data and morphometrics

Sequences of the mitochondrial cytochrome b gene (1063 bp) of Sylvia species from Macaronesia (Canary Islands, Madeira, Azores), Europe, and North Africa revealed new insights into the phylogeography of these taxa. Subspecific distinctiveness for Sardinian warblers (Sylvia melanocephala) from the Canary Islands was rejected on the basis of very low genetic divergence, distribution of haplotypes, and high variation in morphometrics. Furthermore, blackcaps (Sylvia atricapilla) from Madeira, Canary Islands, and the Azores were not genetically distinct, whereas morphometrics were highly variable. Differences in morphometrics in both Sardinian warbler and blackcap are caused rather by migratory behaviour and ecological traits than by phylogeny. Tentative data obtained in a small sample of spectacled warblers (Sylvia conspicillata) also suggest a low degree of differentiation between Sylvia conspicillata orbitalis (Canary Islands) and Sylvia conspicillata conspicillata (Mediterranean basin). At least for the Sardinian warbler and blackcap, the genetic data suggest a recent range expansion and chronologically different colonization events to the Atlantic islands.