Comparative phylogeographic studies often support shared divergence times for co‐distributed species with similar life histories and habitat specializations. During the late Holocene, West Africa experienced aridification and the turnover of rain forest habitats into savannas. These fragmented rain forests harbor impressive numbers of endemic and threatened species. In this setting, populations of co‐distributed rain forest species are expected to have diverged simultaneously, whereas divergence events for species adapted to savanna and forest‐edge habitats should be absent or idiosyncratic. We conducted a Bayesian analysis of shared evolutionary events to test models of population divergence for 20 species of anurans (frogs) and squamates (lizards and snakes) that are distributed across the Dahomey Gap, a climate change‐induced savanna barrier responsible for fragmenting previously contiguous rain forests of Ghana into two regions: the Togo‐Volta Hills and the Southwestern Forests. A model of asynchronous diversification is supported for anurans and squamates, suggesting that drivers of diversification are not specifically related to ecological and life history associations with habitat types. Instead, the wide variability of genetic divergence histories exhibited by these species suggests that biodiversity in this region has been shaped by diversification events that extend beyond the Holocene. Comparisons of the genealogical divergence index, a measure of the genetic divergence between populations due to the combined effects of genetic isolation and gene flow, illustrate that these populations represent a broad sampling of the speciation continuum.

中文翻译：

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西非两栖动物和爬行动物的比较系统地理学

比较系统地理学研究通常支持具有相似生活史和栖息地专业化的共同分布物种的共享发散时间。在全新世晚期，西非经历了干旱化和热带雨林栖息地向稀树草原的转变。这些支离破碎的雨林拥有数量可观的地方性和受威胁物种。在这种情况下，共同分布的雨林物种的种群预计会同时发生分化，而适应热带稀树草原和森林边缘栖息地的物种的分化事件应该不存在或具有异质性。我们对共享进化事件进行了贝叶斯分析，以测试分布在达荷美峡谷的 20 种无尾目（青蛙）和有鳞动物（蜥蜴和蛇）的种群差异模型，气候变化引起的热带稀树草原屏障导致加纳以前连续的热带雨林分裂成两个区域：多哥-沃尔特山和西南森林。无尾目和有鳞类动物支持异步多样化模型，这表明多样化的驱动因素与栖息地类型的生态和生活史关联并不特别相关。相反，这些物种表现出的遗传差异历史的广泛可变性表明，该地区的生物多样性是由超越全新世的多样化事件形成的。系谱差异指数的比较，由于遗传隔离和基因流动的综合影响，衡量种群之间遗传差异的指标，