Data from: Diversification rates and phenotypic evolution in venomous snakes (Elapidae)

The relationship between rates of diversification and of body size change (a common proxy for phenotypic evolution) was investigated across Elapidae, the largest radiation of highly venomous snakes. Time-calibrated phylogenetic trees for 175 species of elapids (more than 50% of known taxa) were constructed using seven mitochondrial and nuclear genes. Analyses using these trees revealed no evidence for a link between speciation rates and changes in body size. Two clades (Hydrophis, Micrurus) show anomalously high rates of diversification within Elapidae, yet exhibit rates of body size evolution almost identical to the general elapid ‘background’ rate. Although correlations between speciation rates and rates of body size change exist in certain groups (e.g. ray-finned fishes, passerine birds), the two processes appear to be uncoupled in elapid snakes. There is also no detectable shift in diversification dynamics associated with the colonization of Australasia, which is surprising given that elapids appear to be the first clade of venomous snakes to reach the continent.

本研究针对眼镜蛇科（Elapidae，全球物种多样性最高的剧毒蛇类类群），探讨了物种分化速率与体型演化速率——表型演化（phenotypic evolution）的常用替代指标——之间的关联。研究基于7个线粒体基因与核基因序列，构建了涵盖175种眼镜蛇科物种（占已知类群50%以上）的时间校准系统发育树（time-calibrated phylogenetic tree）。基于上述系统发育树开展的分析显示，未发现物种分化速率与体型变化速率之间存在关联的证据。两个演化支（海蛇属Hydrophis、珊瑚蛇属Micrurus）在眼镜蛇科中展现出异常高的物种分化速率，但其体型演化速率却与眼镜蛇科整体的“背景”速率几乎一致。尽管在部分类群中（如辐鳍鱼类、雀形目鸟类），物种分化速率与体型变化速率之间存在相关性，但眼镜蛇科蛇类的这两个过程似乎并未解耦。此外，本研究未检测到与澳大拉西亚拓殖事件相关的物种分化动态转变——这一结果颇令人意外，因为眼镜蛇科类群被认为是首批抵达该大陆的有毒蛇类演化支。