Phylogeny of Titmice (Paridae): I. Estimate of Relationships among Subgenera Based on DNA-DNA Hybridization

The phylogenetic relationships of titmice and chickadees (Passeriformes: Paridae) were estimated by DNA-DNA hybridization. Fifteen species of parids (representing all six subgenera) and two outgroups, Penduline Tit Remiz pendulinus and White-breasted Nuthatch Sitta carolinensis, were radiolabeled and compared pairwise to produce a complete reciprocal set of distance measures. The resulting phylogeny supported the traditional allocation of species to subgenera, except that Parus wollweberi clustered with the North American crested tits (subgenus Baeolophus) rather than the Old World crested tits (Lophophanes). The interrelationships of most subgenera remained unresolved. Nevertheless, a major subdivision in the family was strongly indicated: i.e., the great tits (subgenus Parus) and the blue tits (subgenus Cyanistes) formed a clade that is the sister taxon of the rest of the family. This bifurcation has important ecological, physiological, and morphological ramifications, as it correlates exactly with seed-caching and flocking habits, hippocampal development, and leg-muscle character distributions. These DNA-hybridization results corroborate or complement the phylogenetic relationships among parids supported by other molecular data sets (viz., allozyme, restriction site, and preliminary DNA hybridization analyses).