TAXONOMY AND PHYLOGENY OF REED WARBLERS (GENUS ACROCEPHALUS) BASED ONMTDNA SEQUENCES AND MORPHOLOGY

The mitochondrial cytochrome b gene of the majority of Acrocephalus sp ecies (76 individuals) was amplified by PCR and sequenced directly. Nu cleotide sequences (1068 base pairs) were used to reconstruct phylogen etic relationships within the genus Acrocephalus as well as between Ac rocephalus and other sylviid warblers, particularly Hippolais. Acrocep halus and Hippolais share ancestry and cluster in a monophyletic clade . Hippolais appears to represent a polyphyletic assemblage since H. ic terina figures as the sister taxon to Acrocephalus, whereas ''Hippolai s'' pallida and caligata cluster within Acrocephalus. The following Ac rocephalus clades could be recognized: (1) Large reed warblers form a clade consisting of a monophyletic Palearctic-Australasian subgroup (a rundinaceus, stentoreus brunnescens, orientalis, australis, and vaugha ni) and a monophyletic Afrotropical subgroup (brevipennis, rufescens, gracilirostris, sechellensis, and newtoni). A. griseldis holds an isol ated position at the base of the large reed warbler clade. Within the small reed warblers, two probably monophyletic clades are apparent: (2 ) the striped species (with bistrigiceps, melanopogon, paludicola, and schoenobaenus), and (3) the small plain-coloured complex (consisting of dumetorum, palustris, scripaceus, s. fuscus, baeticatus, and avicen niae plus the neighbouring agricola-complex with agricola, tangorum, a nd concinens). The relationship between these groups cannot be resolve d. The molecular data clarify the status of some taxa, the systematic position of which has been controversial. A morphometric analysis (PCA ) of 20 external characters confirmed the basic complexes, and unveile d adaptations of general importance among clades. At species revel, we found less congruence between molecular and morphological data, which can be interpreted as a consequence of specializing adaptations and c onvergence. The major complexes established by molecular and morphomet ric analyses are further supported by distributional, acoustical, and oological affinities. A sound phylogenetic framework of the genus make s it now possible to examine the distribution of ecological and behavi oural characters and to differentiate informative or convergent charac ters. Acrocephalus may be split into four previously recognized genera with the following names: Acrocephalus for the large, Calamodus for t he striped, Notiocichla for the small plain, and Iduna for the brownis h ''Hippolais'' species.