Carl H. Oliveros a , 1 , Daniel J. Field b , c , Daniel T. Ksepka d , F. Keith Barker e , f , Alexandre Aleixo g , Michael J. Andersen h , i , Per Alström j , k , l , Brett W. Benz m , n , o , Edward L. Braun p , Michael J. Braun q , r , Gustavo A. Bravo s , t , u , Robb T. Brumfield a , v , R. Terry Chesser w , Santiago Claramunt x , y , Joel Cracraft m , Andrés M. Cuervo z , Elizabeth P. Derryberry aa , Travis C. Glenn bb , Michael G. Harvey aa , Peter A. Hosner q , cc , Leo Joseph dd , Rebecca T. Kimball p , Andrew L. Mack ee , Colin M. Miskelly ff , A. Townsend Peterson gg , Mark B. Robbins gg , Frederick H. Sheldon a , v , Luís Fábio Silveira u , Brian Tilston Smith m , Noor D. White q , r , Robert G. Moyle gg , Brant C. Faircloth a , v , 1
1 April 2019
Our understanding of the factors that affected the diversification of passerines, the most diverse and widespread bird order (Passeriformes), is limited. Here, we reconstruct passerine evolutionary history and produce the most comprehensive time-calibrated phylogenetic hypothesis of the group using extensive sampling of the genome, complete sampling of all passerine families, and a number of vetted fossil calibration points. Our phylogenetic results refine our knowledge of passerine diversity and yield divergence dates that are consistent with the fossil record, and our macroevolutionary analyses suggest that singular events in Earth history, such as increases in Cenozoic global temperature or the colonization of new continents, were not the primary forces driving passerine diversification.
Avian diversification has been influenced by global climate change, plate tectonic movements, and mass extinction events. However, the impact of these factors on the diversification of the hyperdiverse perching birds (passerines) is unclear because family level relationships are unresolved and the timing of splitting events among lineages is uncertain. We analyzed DNA data from 4,060 nuclear loci and 137 passerine families using concatenation and coalescent approaches to infer a comprehensive phylogenetic hypothesis that clarifies relationships among all passerine families. Then, we calibrated this phylogeny using 13 fossils to examine the effects of different events in Earth history on the timing and rate of passerine diversification. Our analyses reconcile passerine diversification with the fossil and geological records; suggest that passerines originated on the Australian landmass ∼47 Ma; and show that subsequent dispersal and diversification of passerines was affected by a number of climatological and geological events, such as Oligocene glaciation and inundation of the New Zealand landmass. Although passerine diversification rates fluctuated throughout the Cenozoic, we find no link between the rate of passerine diversification and Cenozoic global temperature, and our analyses show that the increases in passerine diversification rate we observe are disconnected from the colonization of new continents. Taken together, these results suggest more complex mechanisms than temperature change or ecological opportunity have controlled macroscale patterns of passerine speciation.