Collaborative Research: The role of habitat transitions in parallel marine fish radiations

鱼类多样性包括金枪鱼、梭鱼和旗鱼等高性能游泳者，它们一生在开阔的海洋中巡航寻找食物(中上层物种)，到行动迟缓、久坐的形式，如生活在海底或附着在植被上的比目鱼或海马体(底栖物种)。体型和习性的很大变化可以通过适应这些鱼生活的栖息地来解释。但生态栖息地对进化过程中导致物种多样化的影响的研究仍然很少。该项目将侧重于两组密切相关的物种，它们蕴藏着巨大的海底和远洋物种多样性(约2000种)，以理清栖息地转变对物种形成和灭绝速度的影响。了解促进形式和习惯多样化的因素对于长期保护海洋生物多样性很重要。合成这些鱼类之间的形态差异所需的创新图像数据分析也将被应用于开发用于智能手机的鱼类物种识别应用程序(FishSnap)，该应用程序将向公众免费提供，未来可扩展到包括所有鱼类。将为本科生和研究生提供教育机会，与华盛顿特区国家自然历史博物馆合作的外联活动将导致一场关于鱼类生物多样性的新的公开展览。最近在鱼类系统发育学方面的研究正在解决物种最丰富的海洋鱼类群体之间关系的长期不确定性，并开辟了前所未有的机会来推断解释其异常多样性的机制。该项目利用新发现的鱼类之间的亲缘关系，揭示了具有底栖和远洋形态的两个独立分支，以调查基因组和形态特征与其生态栖息地之间的联系。研究人员将收集和比较基因组规模的蛋白质编码基因的DNA序列数据集，以推断这两个物种中约800个物种的系统发育树。这棵树将根据精心挑选的化石数据进行时间校准，为比较研究提供一个过时的进化框架。该项目还将汇编一个大型表型(数字图像)数据集，用于形态计量分析。使用最先进的比较方法，这个项目将阐明沿海底-中上层轴线的栖息地转移对形态和谱系多样化速度的影响。将已解决的分子系统学、化石记录、特征和生态数据以及比较方法相结合，将为理解海洋生物多样性的原因提供新的见解。

Fish diversity spans high-performance swimmers such as tunas, barracudas, and swordfish that spend their entire life cruising the open ocean in search of food (pelagic species) to sluggish, sedentary forms such as flounders or seahorses that live buried in the bottom or attached to vegetation (benthic species). Much variation in body form and habit can be explained by adaptation to the habitats where these fishes live. But the effects of ecological habitat on processes leading to diversification over evolutionary time remain poorly explored. This project will focus on two groups of closely related species that harbor a huge diversity of benthic and pelagic forms (about 2000 species) to disentangle the effects of habitat transitions on rates of speciation and extinction. Understanding the factors that promote diversification in form and habit is important for the long-term conservation of marine biodiversity. Innovative image data analysis necessary to synthesize morphological variation among these fishes also will be applied to develop a fish species identification app for smartphones (FishSnap) that will be freely available to the public, expandable in the future to include all fishes. Educational opportunities will be available for undergraduate and graduate students and outreach activities in partnership with the National Museum of Natural History in Washington DC will result in a new public exhibit on fish biodiversity.Recent studies in fish phylogenetics are resolving long-lasting uncertainties about the relationships among the most species-rich marine fish groups, and opening up unprecedented opportunities to infer mechanisms that explain their extraordinary diversity. This project takes advantage of newly discovered affinities among fishes that revealed two independent clades with benthic and pelagic forms to investigate connections between genomic and morphological features in relation to their ecological habitat. The researchers will collect and compare a genome-scale DNA sequence data set of protein-coding genes to infer a phylogenetic tree for about 800 species of these two groups. This tree will be time-calibrated on the basis of carefully selected fossil data to provide a dated evolutionary framework for comparative studies. The project will also assemble a large phenotypic (digital image) dataset of curated specimens for morphometric analysis. Using state-of-the art comparative methodologies, this project will shed light on the effect of habitat shifts along the benthic-pelagic axis on the rate of morphological and lineage diversification. The integration of well-resolved molecular phylogenies, the fossil record, trait and ecological data, and comparative methodologies will provide new insights to understand the causes of marine biodiversity.