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...研究目的：本研究采用全面的地理采样方案与全新的多位点数据集（multilocus dataset），重新解析分布于东南亚的斑条溪蛙的生物地理学特征。我们对比了陆桥岛屿与大洋岛屿上溪蛙种群的多样化模式，并重新评估了此前针对菲律宾多个特有类群起源提出的"双入侵"假说。 研究区域：东南亚、巽他陆架区（Sundaland）以及菲律宾群岛。 研究方法：本研究采集溪蛙样本，对2个线粒体基因区域与2个核基因区域进行测序。通过汇总统计量与系统发育网络，刻画遗传变异的地理分布格局；采用贝叶斯法与似然法估计系统发育关系及祖先生物地理分布范围。最后，基于贝叶斯分析后验分布中的最优拓扑结构与系统发育树，对此前提出的生物地理学"双入侵"拓扑假说进行验证。 研究结果：与预期相悖的是……