Shaffer H Bradley, Fellers G M, Voss S Randal, Oliver J C, Pauly Gregory B
Section of Evolution and Ecology, and Center for Population Biology, University of California, Davis 95616, USA.
Mol Ecol. 2004 Sep;13(9):2667-77. doi: 10.1111/j.1365-294X.2004.02285.x.
The red-legged frog, Rana aurora, has been recognized as both a single, polytypic species and as two distinct species since its original description 150 years ago. It is currently recognized as one species with two geographically contiguous subspecies, aurora and draytonii; the latter is protected under the US Endangered Species Act. We present the results of a survey of 50 populations of red-legged frogs from across their range plus four outgroup species for variation in a phylogenetically informative, approximately 400 base pairs (bp) fragment of the mitochondrial cytochrome b gene. Our mtDNA analysis points to several major results. (1) In accord with several other lines of independent evidence, aurora and draytonii are each diagnosably distinct, evolutionary lineages; the mtDNA data indicate that they do not constitute a monophyletic group, but rather that aurora and R. cascadae from the Pacific northwest are sister taxa; (2) the range of the draytonii mtDNA clade extends about 100 km further north in coastal California than was previously suspected, and corresponds closely with the range limits or phylogeographical breaks of several codistributed taxa; (3) a narrow zone of overlap exists in southern Mendocino County between aurora and draytonii haplotypes, rather than a broad intergradation zone; and (4) the critically endangered population of draytonii in Riverside County, CA forms a distinct clade with frogs from Baja California, Mexico. The currently available evidence favours recognition of aurora and draytonii as separate species with a narrow zone of overlap in northern California.
自150年前首次被描述以来，红腿蛙（Rana aurora）一直被认定为单一的多型物种，也被认为是两个不同的物种。目前它被认定为一个物种，包含两个地理上相邻的亚种，即aurora和draytonii；后者受到美国《濒危物种法》的保护。我们展示了一项调查的结果，该调查涵盖了分布范围内的50个红腿蛙种群以及四个外群物种，以研究线粒体细胞色素b基因中一段约400个碱基对（bp）的系统发育信息片段的变异情况。我们的线粒体DNA分析得出了几个主要结果。（1）与其他几条独立证据一致，aurora和draytonii各自都是可诊断区分的进化谱系；线粒体DNA数据表明它们并不构成一个单系类群，而是来自太平洋西北部的aurora和太平洋树蛙（R. cascadae）是姐妹分类单元；（2）draytonii线粒体DNA分支的分布范围在加利福尼亚州沿海比之前推测的向北延伸了约100公里，并且与几个同域分布分类单元的分布范围界限或系统地理学断点密切对应；（3）在门多西诺县南部，aurora和draytonii单倍型之间存在一个狭窄的重叠区域，而不是一个广泛的渐变区域；（4）加利福尼亚州河滨县极度濒危的draytonii种群与来自墨西哥下加利福尼亚州的青蛙形成了一个独特的分支。目前可得的证据支持将aurora和draytonii认定为两个独立的物种，在加利福尼亚州北部有一个狭窄的重叠区域。
