Fig. 1: Global geographic patterns of speciation rates in amphibians.
From: The latitudinal variation in amphibian speciation rates revisited
Speciation variation in (a) the entire amphibian radiation and within the orders Anura (b), Caudata (c), and Gymnophiona (d). Maps show the geographic distribution of mean speciation rates estimated from tip-level DRs and averaged for each grid cell based on local species assemblages. Plots on the right-hand side show results of SAR’s models evaluating the relationship between mean DR and absolute latitude. Regressions show a trend of increasing speciation rates at higher latitudes, both in the full amphibian radiation (a) and in the case of frogs and toads (b). The pattern is opposite for salamanders (c) where speciation rates increase towards the tropics. For caecilians, no clear pattern of increase or decrease with latitude was (d). The silhouettes used here and in Fig. 3 were obtained from www.phylopic.org/ (Rhacophorus lateralis by Vijay Karthick, Pseudoeurycea amuzga and Dermophis mexicanus by Jose Carlos Arenas-Monroy).
