Data from: Molecular phylogenetics of desmognathine salamanders (Caudata: Plethodontidae): a reevaluation of evolution in ecology, life history, and morphology

Phylogenetic relationships were reconstructed for salamanders of the plethodontid subfamily Desmognathinae to examine evolution of morphology, ecology, and life history. Mitochondrial DNA sequences encoding 12S and 16S ribosomal RNA and the valine transfer RNA provided 259 phylogenetically informative sites from approximately 1,200 nucleotide positions for 21 specimens representing 15 species and subspecies. These data were analyzed in conjunction with 13 morphological and reproductive characters to generate phylogenetic hypotheses. The directly developing terrestrial desmognathines Phaeognathus hubrichti and Desmognathus wrighti represent, respectively, the first and second phylogenetic branching events within the subfamily, and the remaining terrestrial lineage, D. aeneus, also branches near the base of the phylogenetic tree. These results challenge earlier hypotheses that within Desmognathus the small nonmetamorphosing species, D. aeneus and D. wrighti, represent the end of a graded phylogenetic decrease in size and decrease in use of aquatic habitats. In contrast to previous hypotheses, our results suggest that desmognathine evolution includes transformations in the direction of larger body sizes, lengthened larval periods, and greater use of aquatic habitats.

本研究针对无肺螈科（Plethodontidae）德氏螈亚科（Desmognathinae）的蝾螈类重建系统发育关系，以解析其形态、生态及生活史的演化规律。本研究获取的线粒体DNA序列（编码12S核糖体RNA、16S核糖体RNA与缬氨酸转运RNA）在约1200个核苷酸位点中，共获得259个系统发育信息位点，分析样本涵盖代表15个物种及亚种的21号标本。本研究结合13项形态与繁殖性状对上述数据进行分析，以此构建系统发育假说。直接发育型陆生德氏螈类赫氏黑螈（Phaeognathus hubrichti）与赖特德氏螈（Desmognathus wrighti）分别构成该亚科内的首次与第二次系统发育分支事件；其余陆生类群铜色德氏螈（D. aeneus）同样位于系统发育树的基部分支区域。本研究结果对此前的假说提出了挑战：此前假说认为，德氏螈属（Desmognathus）内的小型非变态发育物种铜色德氏螈与赖特德氏螈，代表了系统发育梯度上体型逐渐减小、水生生境利用逐步降低的演化终点。与此前的假说相悖，本研究结果显示德氏螈亚科的演化历程包含向体型增大、幼虫期延长以及水生生境利用程度提升的方向发生的演化转变。