DNA hybridization evidence for the principal lineages of hummingbirds (Aves:Trochilidae

The spectacular evolutionary radiation of hummingbirds (Trochilidae) has served as a model system for many biological studies. To begin to provide a historical context for these investigations, we generated a complete matrix of DNA hybridization distances among 26 hummingbirds and an outgroup swift (Chaeturu pelagica) to determine the principal hummingbird lineages. FITCH topologies estimated from symmetrized AT,H-C values and subjected to various validation methods (bootstrapping, weighted jackknifing, branch length significance) indicated a funda-mental split between hermit (Eutoxeres uquilu, Threnetes ruckeri; Phaethornithinae) and nonhermit (Trochilinae) hummingbirds, and provided strong support for six principal nonhermit clades with the following branching order: (1) a predominantly lowland group comprising caribs (Eulumpis holosericeus) and relatives (Androdon uequutoriuli