Phylogeny and classification of the Old World Emberizini (Aves, Passeriformes)

The phylogeny of the avian genus Emberiza and the monotypic genera Latoucheornis, Melophus and Miliaria (collectively the Old World Emberizini), as well as representatives for the New World Emberizini, the circumpolar genera Calcarius and Plectrophenax and the four other generally recognized tribes in the subfamily Emberizinae was estimated based on the mitochondrial cytochrome b gene and introns 6-7 of the nuclear ornithine decarboxylase (ODC) gene. Our results support monophyly of the Old World Emberizini, but do not corroborate a sister relationship to the New World Emberizini. Calcarius and Plectrophenax form a clade separated from the other Emberizini. This agrees with previous studies, and we recommend the use of the name Calcariini. Latoucheornis, Melophus and Miliaria are nested within Emberiza, and we therefore propose they be synonymized with Emberiza. Emberiza is divided into four main clades, whose relative positions are uncertain, although a sister relation between a clade with six African species and one comprising the rest of the species (30, all Palearctic) is most likely. Most clades agree with traditional, morphology-based, classifications. However, four sister relationships within Emberiza, three of which involve the previously recognized Latoucheornis, Melophus and Miliaria, are unpredicted, and reveal cases of strong morphological divergence. In contrast, the plumage similarity between adult male Emberiza (formerly Latoucheornis) siemsseni and the nominate subspecies of the New World Junco hyemalis is shown to be the result of parallel evolution. A further case of parallel plumage evolution, between African and Eurasian taxa, is pointed out. Two cases of discordance between the mitochondrial and nuclear data with respect to branch lengths and genetic divergences are considered to be the result of introgressive hybridization.