School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia.
The Department of Primary Industries and Regional Development, Perth, Western Australia, Australia.
Biol Lett. 2018 Oct 17;14(10):20180563. doi: 10.1098/rsbl.2018.0563.
Comparative phylogeography can inform many macroevolutionary questions, such as whether species diversification is limited by rates of geographical population differentiation. We examined the link between population genetic structure and species diversification in the fully aquatic sea snakes (Hydrophiinae) by comparing mitochondrial phylogeography across northern Australia in 16 species from two closely related clades that show contrasting diversification dynamics. Contrary to expectations from theory and several empirical studies, our results show that, at the geographical scale studied here, rates of population differentiation and speciation are not positively linked in sea snakes. The eight species sampled from the rapidly speciating clade have weak population differentiation that lacks geographical structure. By contrast, all eight sampled species show clear geographical patterns and many deep intraspecific splits, but have threefold slower speciation rates. Alternative factors, such as ecological specialization, species duration and geographical range size, may underlie rapid speciation in sea snakes.
比较系统地理学可以为许多宏观进化问题提供信息，例如物种多样化是否受到地理种群分化率的限制。我们通过比较两个密切相关的进化枝在澳大利亚北部的 16 种完全水生海蛇（Hydrophiinae）的线粒体系统地理学，研究了种群遗传结构与物种多样化之间的联系，这两个进化枝表现出相反的多样化动态。与理论和几项实证研究的预期相反，我们的研究结果表明，在本研究的地理范围内，海蛇的种群分化率和物种形成率没有正相关关系。从快速形成物种的进化枝中采样的 8 个物种的种群分化较弱，缺乏地理结构。相比之下，所有 8 个采样物种都表现出明显的地理模式和许多深层种内分裂，但物种形成率慢三倍。其他因素，如生态特化、物种持续时间和地理范围大小，可能是海蛇快速物种形成的基础。
