DISSERTATION RESEARCH: Phylogenetic systematics, lineage diversification, and niche evolution in spinetails (Furnariidae, Aves)

确定物种是如何产生的，是理解地球上生物多样性起源和维持的关键。这个项目通过关注一种叫做“刺尾鸟”的非常相似的热带鸟类来解决这个问题，这种鸟类很不寻常，因为它们似乎以令人难以置信的速度进化出了新物种。如果这种快速的物种形成确实是这样的话，对棘尾的研究可能会揭示新物种如何形成的新见解。研究人员将使用遗传技术和尖端的统计分析来确定刺尾的进化史。这项研究将通过共享基因样本和合作对庞大的基因数据集进行复杂的分析来促进国际伙伴关系。该研究还将为有兴趣学习如何应用生物信息学和统计程序设计来回答生态学和进化生物学基本问题的本科生提供研究机会。这项研究的结果将有助于解决长期以来关于刺尾的分类困惑，并提供南美洲生物多样性的更清晰的图景——这是科学和保护的目标。具体来说，研究人员将检验两种关于物种形成的假设。这两种假设都将地理隔离作为一个关键要求，并探讨了种群被隔离的生态背景。一方面，如果同一物种的两个种群生活在不同的环境中，它们可能会由于局部适应而产生生态分化。另外，由于保守的生态偏好，在物种分布中可能存在小的环境差异。如果这种分布被物种的生态偏好之外的区域划分，例如低地物种的山脉，那么扩散将受到极大的限制。这些假设将在多个进化尺度上得到检验。在整个狐螨科中，生态分化率与物种形成之间存在正相关关系。重要的是，树栖刺尾（Cranioleuca属）的生态分化率和物种形成率远远超过该科其他类群。这两个观察结果都支持生态分化与物种形成有关的假设，但为了验证这些假设，需要密集取样的系统发育。本研究将利用基因组尺度的遗传数据集重建树栖刺尾的进化关系。然后，研究人员将采用详细的比较分析来确定这一群体的物种形成是否与生态分化或保守性有关。

Determining the how species are created is key to understanding the origins and maintenance of biodiversity across the planet. This project tackles this issue by focusing on a small set of very similar tropical birds called "spinetails", which are unusual because they appear to have developed new species at an incredibly fast rate. If this rapid speciation is indeed the case, study of spinetails will likely reveal novel insights about how new species come about. Investigators will use genetic techniques and cutting-edge statistical analyses to determine the evolutionary history of spinetails. The study will foster international partnerships through sharing of genetic samples and collaborating on complicated analyses of huge genetic datasets. The study will also provide research opportunities for undergraduates interested in learning how to apply bioinformatics and statistical programming to answer fundamental questions in ecology and evolutionary biology. Results of this study will help resolve long-standing taxonomic confusion about spinetails and provide a clearer picture of South American biodiversity -- a goal of both science and conservation.Specifically, the investigators will test two alternative hypotheses of speciation. Both hypotheses rely on geographic isolation as a key requirement and explore the ecological context in which populations become isolated. On the one hand, if two populations of the same species occur in different environments it may cause to them to diverge ecologically due to local adaptation. Alternatively, small environmental differences may exist within a species' distribution due to conserved ecological preferences. If this distribution is divided by a region outside the species' ecological preference, such as mountains for a lowland species, dispersal will be greatly restricted. These hypotheses will be tested at multiple evolutionary scales. Across Furnariidae, there is a positive relationship between the rate of ecological divergence and speciation. Importantly, the arboreal spinetails (genus Cranioleuca) exhibit rates of ecological divergence and speciation far exceeding those found in other groups in the family. Both observations support the hypothesis that ecological divergence is associated with speciation, but to test these hypotheses a densely sampled phylogeny is needed. This study will reconstruct the evolutionary relationships of the arboreal spinetails using genomic scale genetic datasets. Investigators will then employ detailed comparative analyses to determine if speciation in this group is associated with ecological divergence or conservatism.