Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, 66045.
Evolution. 2013 Dec;67(12):3556-72. doi: 10.1111/evo.12219. Epub 2013 Aug 26.
An accurate understanding of species diversity is essential to studies across a wide range of biological subdisciplines. However, delimiting species remains challenging in evolutionary radiations where morphological diversification is rapid and accompanied by little genetic differentiation or when genetic lineage divergence is not accompanied by morphological change. We investigate the utility of a variety of recently developed approaches to examine genetic and morphological diversity, and delimit species in a morphologically conserved group of Southeast Asian lizards. We find that species diversity is vastly underestimated in this unique evolutionary radiation, and find an extreme case where extensive genetic divergence among lineages has been accompanied by little to no differentiation in external morphology. Although we note that different conclusions can be drawn when species are delimited using molecular phylogenetics, coalescent-based methods, or morphological data, it is clear that the use of a pluralistic approach leads to a more comprehensive appraisal of biodiversity, and greater appreciation for processes of diversification in this biologically important geographic region. Similarly, our approach demonstrates how recently developed methodologies can be used to obtain robust estimates of species limits in "nonadaptive" or "cryptic" evolutionary radiations.
准确理解物种多样性对于广泛的生物学子学科的研究至关重要。然而，在形态多样化迅速且遗传分化较小的进化辐射中，或者在遗传谱系分化不伴随形态变化时，物种的界定仍然具有挑战性。我们研究了各种最近开发的方法在检查遗传和形态多样性以及在形态保守的东南亚蜥蜴群中界定物种方面的效用。我们发现，在这种独特的进化辐射中，物种多样性被大大低估了，并且发现了一个极端情况，即谱系之间存在广泛的遗传分歧，但外部形态几乎没有分化。尽管我们注意到，当使用分子系统发生学、基于合并的方法或形态数据来界定物种时，可以得出不同的结论，但显然，采用多元化的方法可以更全面地评估生物多样性，并更好地了解这个在生物上重要的地理区域的多样化过程。同样，我们的方法表明，最近开发的方法如何可用于在“非适应性”或“隐匿性”进化辐射中获得物种界限的稳健估计。
