Salerno P E, Señaris J C, Rojas-Runjaic F J M, Cannatella D C
Department of Integrative Biology and Texas Natural History Collections, University of Texas at Austin, 1, University Station, C0990, Austin, TX 78712, USA.
Centro de Ecología, Instituto Venezolano de Investigaciones Científicas, Apartado 20632, Caracas 1020-A, Venezuela.
Mol Phylogenet Evol. 2015 Jan;82 Pt A:314-23. doi: 10.1016/j.ympev.2014.10.020. Epub 2014 Nov 1.
The tepuis of South America are massive flattop mountains with cliffs up to 1000m and summits up to 3100m. Tepuis hold enormous endemicity levels, but little is known about the origins of the endemic flora and fauna. Recently diverged lineages offer the possibility of understanding the origins of summit endemicity by examining population dynamics and dispersal. We examine species delimitation, clade relationships, and demographic patterns of three recently diverged lineages of Tepuihyla, an endemic treefrog clade. These three lineages represent two currently recognized species, T. edelcae and T. rodriguezi. Given the low divergences in both nuclear and mitochondrial genes among lineages, we find unexpectedly high numbers of unique nuclear haplotypes and moderate levels of lineage sorting. We also find support from multiple analyses for a cryptic, undescribed summit species within T. edelcae. We suggest that the genetic and distribution patterns of the four most recently diverged Tepuihyla lineages support a concurrent speciation event during the Pliocene, and suggest a biogeographic hypothesis in which a widespread climatic change made mid- and low-elevation habitat unsuitable for the common ancestor within the timeframe of their divergence.
南美洲的特普伊山是巨大的平顶山脉，悬崖高达1000米，山峰高达3100米。特普伊山拥有极高的特有物种丰富度，但对于其特有动植物群的起源却知之甚少。最近分化出的谱系为通过研究种群动态和扩散来理解山顶特有性的起源提供了可能性。我们研究了特普伊雨蛙属（一种特有树蛙类群）三个最近分化出的谱系的物种界定、分支关系和种群模式。这三个谱系代表了两个目前已被认可的物种，即埃氏特普伊雨蛙和罗氏特普伊雨蛙。鉴于各谱系在核基因和线粒体基因方面的低分化程度，我们意外地发现了大量独特的核单倍型以及中等程度的谱系分选。我们还从多项分析中获得证据，支持在埃氏特普伊雨蛙中存在一个隐秘的、未被描述的山顶物种。我们认为，四个最近分化出的特普伊雨蛙谱系的遗传和分布模式支持了上新世期间的一次同时发生的物种形成事件，并提出了一个生物地理学假设，即在其分化的时间范围内，广泛的气候变化使中低海拔栖息地对共同祖先不再适宜。
