Data from: Going to extremes: contrasting rates of diversification in a recent radiation of New World passerine birds

Recent analyses suggest that a few major shifts in diversification rate may be enough to explain most of the disparity in diversity among vertebrate lineages. At least one significant increase in diversification rate appears to have occurred within the birds; however, several nested lineages within birds have been identified as hyperdiverse by different studies. A clade containing the finches and relatives (within the avian order Passeriformes), including a large radiation endemic to the New World that comprises ~8% of all bird species, may be the true driver of this rate increase. Understanding the patterns and processes of diversification of this diverse lineage may go a long way toward explaining the apparently rapid diversification rates of both passerines and of birds as a whole. We present the first multi-locus phylogenetic analyses of this endemic New World radiation of finch relatives that includes sampling of all recognized genera, a relaxed molecular clock analysis of its divergence history, and an analysis of its broad-scale diversification patterns. These analyses recover five major lineages traditionally recognized as avian families, but identify an additional ten relatively ancient lineages worthy of recognition at the family level. Time-calibrated diversification analyses suggest that at least six of the fifteen family-level lineages are significantly species-poor given the entire group's background diversification rate, whereas one—the tanagers of family Thraupidae—is significantly more diverse. These differences are consistent with the low speciation and extinction rates of island and ecologically-specialized lineages previously documented across passerines as a whole. Finally, lack of an age-diversity relationship within this clade suggests that, due to rapid initial speciation, it may have experienced density-dependent ecological limits on its overall diversity.