Data from: Effects of climatic and geological processes during the Pleistocene on the evolutionary history of the northern cavefish, Amblyopsis spelaea (Teleostei: Amblyopsidae)

Climatic and geological processes associated with glaciation cycles during the Pleistocene have been implicated in influencing patterns of genetic variation and promoting speciation of temperate flora and fauna. However, determining the factors promoting divergence and speciation is often difficult in many groups because of our limited understanding of potential vicariant barriers and connectivity between populations. Pleistocene glacial cycles are thought to have significantly influenced the distribution and diversity of subterranean invertebrates; however, impacts on subterranean aquatic vertebrates are less clear. We employed several hypothesis-driven approaches to assess the impacts of Pleistocene climatic and geological changes on the Northern Cavefish, Amblyopsis spelaea, whose current distribution occurs near the southern extent of glacial advances in North America. Our results show that the modern Ohio River has been a significant barrier to dispersal and is correlated with patterns of genetic divergence. We infer that populations were isolated in two refugia located north and south of the Ohio River during the most recent two glacial cycles with evidence of demographic expansion in the northern isolate. Finally, we conclude that climatic and geological processes have resulted in the formation of cryptic forms and advocate recognition of two distinct phylogenetic lineages currently recognized as Amblyopsis spelaea.

更新世（Pleistocene）冰期循环相关的气候与地质过程，被认为可影响温带动植物的遗传变异格局并推动其物种形成。然而，由于对种群间潜在的异域隔离屏障与连通性认识不足，诸多类群中推动分化与物种形成的因素往往难以确定。更新世冰期循环被认为对地下无脊椎动物的分布与多样性产生了显著影响，但针对地下水生脊椎动物的相关影响尚不明晰。本研究采用多种假说驱动的研究方法，评估更新世气候与地质变化对北方穴居鱼（Amblyopsis spelaea）的影响；该物种当前的分布范围位于北美冰川推进最南界附近。研究结果显示，现代俄亥俄河（Ohio River）是重要的扩散屏障，并与遗传分化格局显著相关。我们推断，在最近两次冰期循环中，该物种种群被隔离在俄亥俄河以北与以南的两处避难所中，且北部隔离种群存在种群扩张的证据。综上，本研究认为气候与地质过程促成了隐存类群的形成，并主张将当前被归为北方穴居鱼（Amblyopsis spelaea）的类群划分为两个独立的系统发育谱系。