ORIGINAL ARTICLE doi:10.1111/j.1558-5646.2009.00610.x EVOLUTIONARY AND BIOGEOGRAPHIC ORIGINS OF HIGH TROPICAL DIVERSITY IN OLD WORLD FROGS (RANIDAE) John J. Wiens,1,2 Jeet Sukumaran,3 R. Alexander Pyron4 and Rafe M. Brown3 1Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York 11794 2E-mail:
[email protected] 3Natural History Museum, Biodiversity Research Center, Department of Ecology and Evolutionary Biology, University of Kansas, Dyche Hall, Lawrence, Kansas 66045-7561 4Department of Biology, The Graduate School and University Center, City University of New York, New York, New York 10016 Received May 24, 2008 Accepted November 17, 2008 Differences in species richness between regions are ultimately explained by patterns of speciation, extinction, and biogeographic dispersal. Yet, few studies have considered the role of all three processes in generating the high biodiversity of tropical regions. A recent study of a speciose group of predominately New World frogs (Hylidae) showed that their low diversity in temperate regions was associated with relatively recent colonization of these regions, rather than latitudinal differences in diversification rates (rates of speciation–extinction). Here, we perform parallel analyses on the most species-rich group of Old World frogs (Ranidae; ∼1300 species) to determine if similar processes drive the latitudinal diversity gradient. We estimate a time-calibrated phylogeny for 390 ranid species and use this phylogeny to analyze patterns of biogeography and diversification rates. As in hylids, we find a strong relationship between the timing of colonization of each region and its current diversity, with recent colonization of temperate regions from tropical regions.