Dissertation Research: Processes of Diversification and Evolutionary History of Web-toed Salamanders (Genus Hydromantes)

这个项目的目的是了解导致内华达山脉两种鳍趾火蜥蜴物种分化的进化过程。其中一种分布较广，另一种分布较小，在形态和栖息地上存在差异。遗传证据表明，受范围限制的物种最近可能与广布物种发生了分歧，广布物种的不同部分已经相互隔离了数百万年。过去的气候变化和地质过程对这些物种内部和之间的遗传分化的相对影响将使用各种不同的遗传标记并结合分布模型进行调查。这些火蜥蜴提供了研究一些种群的机会，这些种群具有显著的遗传差异但形态相似，以及其他在形态上差异但遗传相似的种群。研究气候变化和地理障碍在塑造这些物种内遗传分化的分布和模式方面的相对作用，将有助于我们进一步理解谱系和物种是如何形成的，这是进化生物学的一个主要焦点。增加对神秘的生物多样性和物种对过去环境变化的反应的知识，对于保护工作也是很有价值的，特别是在未来气候变化可能产生的影响方面。

The aim of this project is to understand the evolutionary processes that have led to divergence between two species of web-toed salamanders in the Sierra Nevada. One species (Hydromantes platycephalus) is widespread and the other (H. brunus) is restricted to a small area, and the species show differences in morphology and habitat. Genetic evidence indicates that the range-restricted species may have recently diverged from the widespread species, and that different segments of the widespread species have been isolated from one another for millions of years. The relative influence of past climate changes and geological processes on genetic divergence within and between these species will be investigated using a variety of different genetic markers, in combination with distributional modeling.These salamanders offer the opportunity to study some populations with striking levels of genetic divergence but high morphological similarity, and others that are morphologically divergent but genetically similar. Examining the relative roles of climatic changes and geographic barriers in shaping the distributions and patterns of genetic divergence within these species will further our understanding of how lineages and species form, a major focus of evolutionary biology. Increased knowledge of cryptic biodiversity and species' responses to past environmental change will also be valuable for conservation efforts, especially with respect to the probable impact of future climate change.