title: Minimal effects of latitude on present-day speciation rates in New World birds.
abstract: The tropics contain far greater numbers of species than temperate regions, suggesting that rates of species formation might differ systematically between tropical and non-tropical areas. We tested this hypothesis by reconstructing the history of speciation in New World (NW) land birds using BAMM, a Bayesian framework for modelling complex evolutionary dynamics on phylogenetic trees. We estimated marginal distributions of present-day speciation rates for each of 2571 species of birds. The present-day rate of speciation varies approximately 30-fold across NW birds, but there is no difference in the rate distributions for tropical and temperate taxa. Using macroevolutionary cohort analysis, we demonstrate that clades with high tropical membership do not produce species more rapidly than temperate clades. For nearly any value of present-day speciation rate, there are far more species in the tropics than the temperate zone. Any effects of latitude on speciation rate are marginal in comparison to the dramatic variation in rates among clades.
authors.affiliation: Department of Ecology and Evolutionary Biology and Museum of Zoology, University of Michigan, Ann Arbor, MI 48109, USA drabosky@umich.edu.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Rabosky
authors.affiliation: Department of Ecology and Evolutionary Biology and Museum of Zoology, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Pascal O
authors.initials: PO
authors.lastname: Title
authors.affiliation: Department of Ecology and Evolutionary Biology and Museum of Zoology, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Huateng
authors.initials: H
authors.lastname: Huang
mesh_terms: D000569:Americas; D063147:Animal Distribution; D000818:Animals; D001499:Bayes Theorem; D044822:Biodiversity; D005075:Biological Evolution; D001717:Birds / Q000235:genetics / Q000502:physiology*; D049810:Genetic Speciation; D008957:Models, Genetic; D014329:Tropical Climate
keywords: diversification; diversity-dependence; latitudinal diversity gradient; macroevolution; speciation