Department of Biology, University of Central Florida, 4110 Libra Drive, Orlando, FL 32816, USA; Department of Ecology and Evolutionary Biology, University of Toronto, 25 Wilcocks St., Toronto, ON M5S 3B2, Canada(1).
Department of Biology, University of Central Florida, 4110 Libra Drive, Orlando, FL 32816, USA; Department of Biological Sciences, Clemson University, 190 Collings St., Clemson, SC 29634, USA(1).
Mol Phylogenet Evol. 2018 Dec;129:214-225. doi: 10.1016/j.ympev.2018.08.018. Epub 2018 Sep 3.
Accurate representation of lineage diversity through complete taxon sampling is crucial to understanding the evolution of biodiversity, particularly when using molecular phylogenetics to estimate evolutionary relationships. In this interest, taxonomic diversity is often used as a proxy for lineage diversity even though the two concepts are not synonymous. We explore this within the snake tribe Lampropeltini which includes some of the most conspicuous and heavily studied snakes in North America. Both the taxonomy and hypothesized relationships within this tribe have been in flux. The number of species has increased from 23 to 51 over the last thirty years, predominately within three of the nine genera (Lampropeltis, Pantherophis, Pituophis). The remaining six depauperate genera (Arizona, Bogertophis, Cemophora, Pseudelaphe, Rhinocheilus, and Senticolis) have been poorly represented in phylogenetic studies. To estimate evolutionary relationships and determine if the dichotomy in depauperate and speciose genera within Lampropeltini is a function of taxon sampling or truly represents the lineage diversity, we estimated the phylogeny of this group using nuclear and mitochondrial loci in a concatenated and coalescent framework with the largest sampling of the six depauperate genera to date. In addition, we estimated the divergence dates among the genera to assess whether the instability of Lampropeltini phylogenetic relationships is due to an adaptive radiation. While some nodes still remain unresolved, the generic-level relationships we recovered agree with those of a recent next-generation study that used a much larger set of loci for fewer individuals. We also tested two putative species, Arizona pacata and Pseudelaphe phaescens, for the first time phylogenetically and find evidence that they are distinct lineages. Overall, we find that the taxonomic and genetic diversity are not correlated in Lampropeltini and that representing putative diversity in phylogenies will lead to a better estimate of evolutionary histories, especially in groups with complex radiations.
通过完整的分类群采样准确表示谱系多样性对于理解生物多样性的进化至关重要，特别是在使用分子系统发育学估计进化关系时。在这方面，分类多样性通常用作谱系多样性的代理，尽管这两个概念并不相同。我们在包括北美最显眼和研究最多的蛇之一的 Lampropeltini 蛇族中探讨了这一点。该部落的分类学和假设的关系一直在变化。在过去的三十年中，物种数量从 23 种增加到 51 种，主要集中在九个属中的三个（Lampropeltis、Pantherophis、Pituophis）。其余六个贫乏的属（Arizona、Bogertophis、Cemophora、Pseudelaphe、Rhinocheilus 和 Senticolis）在系统发育研究中代表性较差。为了估计进化关系并确定 Lampropeltini 内贫乏和多样化属的二分法是分类群采样的结果还是真正代表谱系多样性，我们使用核和线粒体基因座在一个并系和合并框架中估计了这个群体的系统发育，这是迄今为止对六个贫乏属进行的最大采样。此外，我们估计了属之间的分歧日期，以评估 Lampropeltini 系统发育关系的不稳定性是否是由于适应性辐射。虽然有些节点仍然没有解决，但我们恢复的属级关系与最近一项使用更多基因座对较少个体进行的下一代研究的结果一致。我们还首次对两个假定的物种，即 Arizona pacata 和 Pseudelaphe phaescens，进行了系统发育分析，并发现它们是不同的谱系。总体而言，我们发现 Lampropeltini 中的分类和遗传多样性没有相关性，并且在系统发育中代表假定的多样性将更好地估计进化历史，特别是在具有复杂辐射的群体中。
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