The New World blackbirds (Icteridae) are among the best known songbirds, serving as a model clade in comparative studies of morphological, ecological, and behavioral trait evolution. Despite wide interest in the group, as yet no analysis of blackbird relationships has achieved comprehensive species-level sampling or found robust support for most intergeneric relationships. Using mitochondrial gene sequences from all ~108 currently recognized species and six additional distinct lineages, together with strategic sampling of four nuclear loci and whole mitochondrial genomes, we were able to resolve most relationships with high confidence. Our phylogeny is consistent with the strongly-supported results of past studies, but it also contains many novel inferences of relationship, including unexpected placement of some newly-sampled taxa, resolution of relationships among major clades within Icteridae, and resolution of genus-level relationships within the largest of those clades, the grackles and allies. We suggest taxonomic revisions based on our results, including restoration of Cacicus melanicterus to the monotypic Cassiculus, merging the monotypic Ocyalus and Clypicterus into Cacicus, restoration of Dives atroviolaceus to the monotypic Ptiloxena, and naming Curaeus forbesi to a new genus, Anumara. Our hypothesis of blackbird phylogeny provides a foundation for ongoing and future evolutionary analyses of the group.
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We are grateful to A.J. Vandergon, who did much of the lab work involved in obtaining nuclear sequences, A.H. Vázquez-Miranda, who performed some extractions, and G.D. Weiblen, who allowed use of his lab for preparing toe pad samples. We thank the museums that loaned tissues for sequencing that was new to this project—the Academy of Natural Sciences of Drexel University; American Museum of Natural History; Field Museum of Natural History; Natural History Museum of Los Angeles County; Louisiana State University Museum of Natural Science; Museo Argentino de Ciencias Naturales, Bernardino Rivadavia; Marjorie Barrick Museum of Natural History; Museu Paraense Emílio Goeldi; Florida Museum of Natural History; and the Burke Museum of Natural History and Culture—as well as the many others (listed in Table 1 ) that maintain specimens associated with GenBank sequences that we used. M.B. Robbins, A. G. Navarro-Sigüenza and A. Aleixo helped by checking identities of some vouchers. We also thank J.C. Avise, D. Walker, J.M. DaCosta, K.E. Omland, and F. Jacobsen for providing samples or sequences. A. Aleixo, E.C. Dickinson, and S. Gregory provided advice on nomenclature. S.A. Jansa made useful comments on the draft manuscript. This study was supported in part by NSF DEB-0316092 to FKB and SML and by the University of Minnesota.
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