Collaborative Research: Phylogeny and Montane Species Richness in Plethodontid Salamanders

研究人员将利用形态学和分子数据重建plethodontid蝾螈的进化史，然后利用进化史探索物种多样性如何随海拔变化，以及物种丰富度模式的进化原因。 Plethodontidae是蝾螈中最大的家族，包含了所有460多种蝾螈中的三分之二。 Plethodontids可能是北美东部最丰富的脊椎动物，并且是许多不同生物学领域的数十位科学家的研究重点（例如，生态学、行为学、形态学、进化、发育）。 这些研究中的许多（如果不是大多数）关键取决于是否有一个强大的系统发育框架。 然而，plethodontids之间的更高层次的关系从来没有使用现代方法进行全面研究的主题。在一项为期三年的合作研究中，PI将利用形态特征和来自两个线粒体基因和一个核基因的DNA序列重建112种plethodontid蝾螈（加上代表其他五个家族的外群）的生殖发育。 物种发生学将用于探索物种多样性如何以及为什么随着海拔的变化而变化，使用阿巴拉契亚山脉异常丰富的蝾螈动物群作为模型系统。 相对于低地地区，许多生物群体在山区的物种多样性有所增加，这是一种普遍存在的模式，但对此解释不清。 在此建议，这种模式的结果，在山区的山地栖息地和高地物种的海拔栖息地特异性的分离性所造成的物种形成增加。 该模型的三个关键预测将使用系统发育方法进行测试。 这项研究将提供基于形态学和分子数据的严格分析的第一个plethodontid蝾螈的生殖系统。对于数十名使用plethodontids作为生态学，行为，进化，发育和其他生物学领域研究模型系统的研究人员来说，这一系统发育将是至关重要的。这项研究也将是第一个从系统发育的角度来解决物种丰富度的海拔模式。 这些山地物种丰富度的分析应该有重要的生态学，进化，地理学和保护生物学领域的影响。例如，分析海拔特异性（一个物种对给定海拔范围及其相关气候的适应程度）对于预测山区物种在全球变暖或其他气候变化方面的持续存在或灭绝可能很重要。 这项研究将为本科生和研究生以及一名博士后研究员提供分子技术和生物学、生态学和进化综合分析方面的培训。

The investigators will reconstruct the phylogeny of plethodontid salamanders using morphological and molecular data and then use the phylogeny to explore how species diversity changes with elevation, and the evolutionary reasons for patterns of species richness. Plethodontidae is the largest family of salamanders, containing about two-thirds of all 460+ species of salamanders. Plethodontids are possibly the most abundant vertebrates in eastern North America and are the focus of research by dozens of scientists in many diverse fields of biology (e.g., ecology, behavior, morphology, evolution, development). Many (if not most) of these studies depend critically on having a robust phylogenetic framework. However, higher-level relationships among plethodontids have never been the subject of a comprehensive study using modern methods. In a three-year collaborative study, the PIs will reconstruct the phylogeny of 112 species of plethodontid salamanders (plus outgroups representing five other families) using morphological characters and DNA sequences from two mitochondrial genes and one nuclear gene. The phylogeny will be used to explore how and why species diversity changes with elevation, using the unusually rich salamander fauna of the Appalachian Mountains as a model system. Many groups of organisms exhibit increased species diversity in montane areas relative to lowland areas, a widespread pattern that remains poorly explained. It is suggested herein that this pattern results from increased speciation in montane regions caused by the disjunctive nature of montane habitats and the elevational habitat specificity of highland species. Three key predictions of this model will be tested using phylogenetic methods. The study will provide the first phylogeny of plethodontid salamanders based on a rigorous analysis of morphological and molecular data. The phylogeny will be critical to dozens of researchers who use plethodontids as a model system in studies of ecology, behavior, evolution, development, and other areas of biology. The study will also be the first to address elevational patterns of species richness from a phylogenetic perspective. These analyses of montane species richness should have important implications for the fields of ecology, evolution, biogeography, and conservation biology. For example, the analyses of elevational specificity (how narrowly adapted a species is to a given elevational range and its associated climate) may be important for predicting the persistence or extinction of montane species in relation to global warming or other changes in climate. The study will provide training for undergraduate and graduate students and a postdoctoral fellow in molecular techniques and in integrated analyses of phylogeny, ecology, and evolution.