Data from: Repeated evolution of amphibious behavior in fish and its implications for the colonization of novel environments

We know little about on how frequently transitions into new habitats occur, especially the colonization of novel environments that are the most likely to instigate adaptive evolution. One of the most extreme ecological transitions has been the shift in habitat associated with the move from water to land by amphibious fish. We provide the first phylogenetic investigation of these transitions for living fish. Thirty-three families have species reported to be amphibious and these are likely independent evolutionary origins of fish emerging onto land. Phylogenetic reconstructions of closely related taxa within one of these families, the Blenniidae, inferred as many as seven convergences on a highly amphibious lifestyle. Taken together, there appear to be few constraints on fish emerging onto land given amphibious behavior has evolved repeatedly many times across ecologically diverse families. The colonization of novel habitats by other taxa resulting in less dramatic changes in environment should be equally, if not, more frequent in nature, providing an important prerequisite for subsequent adaptive differentiation.

我们对生物迁入新栖息地的频率所知甚少，尤其是那些最有可能引发适应性进化（adaptive evolution）的全新生境定植事件。两栖鱼类从水生向陆生的生境转变，是最为极端的生态转变之一。本研究首次针对现生鱼类的这类生境转变开展系统发育（phylogenetic）调查。目前已有33个鱼类科被报道存在两栖物种，这些类群的陆生登陆行为很可能均为独立演化起源。对其中一个类群——鳚科（Blenniidae）内的近缘类群进行的系统发育重建结果显示，其高度两栖的生活方式至少经历了7次趋同演化（convergent evolution）事件。综合来看，鉴于两栖行为在多个生态多样的鱼类类群中多次独立演化，鱼类登陆行为似乎几乎不受演化约束。其他类群在仅引发相对平缓环境变化的情况下完成全新生境定植的事件，即便不比鱼类登陆更频繁，也至少与之相当；而这类事件正是后续适应性分化的重要先决条件。