Data from: Convergence across a continent: adaptive diversification in a recent radiation of Australian lizards

Recent radiations are important to evolutionary biologists, because they provide an opportunity to study the mechanisms that link micro- and macroevolution. The role of ecological speciation during adaptive radiation has been intensively studied, but radiations can arise from a diversity of evolutionary processes; in particular, on large continental landmasses where allopatric speciation might frequently precede ecological differentiation. It is therefore important to establish a phylogenetic and ecological framework for recent continental-scale radiations that are species-rich and ecologically diverse. Here, we use a genomic (approx. 1 200 loci, exon capture) approach to fit branch lengths on a summary-coalescent species tree and generate a time-calibrated phylogeny for a recent and ecologically diverse radiation of Australian scincid lizards; the genus Cryptoblepharus. We then combine the phylogeny with a comprehensive phenotypic dataset for over 800 individuals across the 26 species, and use comparative methods to test whether habitat specialization can explain current patterns of phenotypic variation in ecologically relevant traits. We find significant differences in morphology between species that occur in distinct environments and convergence in ecomorphology with repeated habitat shifts across the continent. These results suggest that isolated analogous habitats have provided parallel ecological opportunity and have repeatedly promoted adaptive diversification. By contrast, speciation processes within the same habitat have resulted in distinct lineages with relatively limited morphological variation. Overall, our study illustrates how alternative diversification processes might have jointly stimulated species proliferation across the continent and generated a remarkably diverse group of Australian lizards.

近期演化辐射事件对进化生物学家而言具有重要意义，因其为研究连接微观进化与宏观进化的机制提供了绝佳契机。适应辐射（adaptive radiation）过程中生态物种形成（ecological speciation）的作用已得到广泛研究，但演化辐射可由多种进化过程驱动；尤其是在大型大陆陆块上，异域物种形成（allopatric speciation）往往先于生态分化发生。因此，针对物种丰富且生态多样的大陆尺度近期演化辐射类群，构建系统发育与生态框架具有重要意义。本研究采用基因组学方法（约1200个基因座，外显子捕获（exon capture）技术），在溯祖总结物种树（summary-coalescent species tree）上拟合分支长度，并为近期且生态多样的澳大利亚石龙子科（Scincidae）蛇眼蜥属（Cryptoblepharus）演化辐射类群构建时间校准系统发育树（time-calibrated phylogeny）。随后，本研究将该系统发育树与涵盖26个物种、800余只个体的综合表型（phenotypic）数据集相结合，并采用比较生物学（comparative biology）方法检验生境特化是否能够解释生态相关性状的当前表型变异模式。研究发现，栖息于不同环境的物种间形态存在显著差异，且在全大陆范围内多次生境转变过程中，生态形态学（ecomorphology）特征呈现趋同演化。上述结果表明，孤立的相似生境提供了平行的生态机遇，并反复推动了适应辐射。与之相反，同一生境内的物种形成过程则产生了形态变异相对有限的不同演化支系。综上，本研究阐明了多种差异化的多样化过程如何共同推动了全大陆的物种增殖，并塑造了澳大利亚蜥蜴类极为丰富的类群。