Phylogeny of the genus Hirundo and the Barn Swallow subspecies complex.

The cosmopolitan Barn Swallow complex (Hirundo rustica and related Hirundo species) provides a model system for studies of mate choice, sexual selection, and related topics in behavioral ecology, but the phylogenetic and phylogeographic relationships within this group are not yet completely resolved. We reconstructed the phylogeny of all 14 species of Hirundo as well as all six Barn Swallow (H. rustica) subspecies using maximum likelihood and Bayesian methods based on sequences of mitochondrial DNA from six protein-coding genes (5217 bp) and one nuclear intron (1039 bp) for most taxa. We found four well-supported clades within the genus, but low support values for one node decreased our ability to determine the relationships among them. H. rustica is recently derived and has a wide geographic distribution, and its six subspecies form a monophyletic group with respect to other Hirundo species. These subspecies divide into two well-supported clades, geographically corresponding to Asia-America and Europe-Middle East. The former comprises two groups, an East Asian subspecies that is sister to Southeast Asian, American, and Northwest Asian subspecies. In the other clade, European and East-Mediterranean subspecies are intermixed and both show some divergence from the Egyptian subspecies.