Spotted stream frog diversification at the Australasian faunal zone interface, mainland versus island comparisons, and a test of the Philippine ‘dual-umbilicus’ hypothesis

Aim: We utilize comprehensive geographical sampling and a new, multilocus dataset to re-examine the biogeography of spotted stream frogs throughout Southeast Asia. We compare patterns of diversification among stream frog populations on land-bridge islands and oceanic islands and we reevaluate a previous ‘dual-invasion’ hypothesis for the origins of several endemic Philippine taxa. Location: Southeast Asia, Sundaland, and the Philippines. Methods: Stream frogs were collected and sequenced for two mitochondrial and two nuclear gene regions. We used summary statistics and phylogenetic networks to characterize the geographic distribution of genetic variation. Phylogenetic relationships and ancestral biogeographic ranges were estimated using Bayesian and likelihood methods. Finally, we used the preferred topology and trees from the posterior distribution of the Bayesian analyses to evaluate a previous biogeographic ‘dual-invasion’ topological hypothesis. Results: In contrast to expectation...