MOLECULAR DIVERGENCE IN TWO MEDITERRANEAN SONGBIRD SPECIES OF THE GENUS SYLVIA (AVES: SYLVIIDAE): IMPLICATIONS FOR TAXONOMY AND RESEARCH

Mediterranean region is one of world’s best explored areas in terms of ornithological research and it is considered a main biodiversity hotspot for the Western Palearctic (Myers et al. 2000), especially because it played a fundamental role in the divergence and speciation processes for many taxa, due to dynamics linked mainly to glaciations and salinity crises (Hewitt 1996; Taberlet et al. 1998). Most taxonomical research in ornithology carried on within this region has been based on anatomical and morphological differentiation of populations; this could have led to underestimating the real degree of divergence occurring in some morphologically cryptic populations in the region. We here analyse genetic divergence in two Sylvia (Aves: Sylviidae) species, formerly suspected of hiding complexes of cryptic sister species. We demonstrate the existence of complete molecular diagnosability and strong patterns of structuration of molecular variability in mitochondrial and nuclear markers for two taxa, which we propose to elevate to the rank of Confirmed Candidate Species (Galimberti et al. 2012): Sylvia [sarda] balearica and western Sylvia [cantillans] cantillans. We simultaneously urge the need to properly re-evaluate conservation status and policies for at least Sylvia [sarda] balearica, endemic to only a small archipelago. Molecular identification of migrating and wintering individuals of Sylvia [cantillans] allowed us to gather the first certain data about the wintering areas of single taxon of the species complex and to highlight a pattern of great dynamism in their yearly trajectories. We suggest expanding our preliminary research by coupling a more capillary distribution of ringing efforts in Northern and Central Africa with molecular identifications of trapped individuals.