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

鱼类的多样性从高性能游泳者，如金枪鱼、梭鱼和剑鱼，它们一生都在开阔的海洋中巡游寻找食物（远洋物种）到懒散、久坐的形式，如比目鱼或海马，它们生活在海底或附着在植被上（底栖物种）。体型和习性的许多变化可以用对这些鱼类生活的栖息地的适应来解释。但是，在进化过程中，生态栖息地对导致物种多样化的过程的影响仍未得到充分探索。该项目将重点研究两组密切相关的物种，它们拥有巨大的底栖生物和远洋生物多样性（约2000种），以解开栖息地转变对物种形成和灭绝速度的影响。了解促进形式和习性多样化的因素对海洋生物多样性的长期保护很重要。综合这些鱼类形态变化所需的创新图像数据分析也将应用于开发智能手机鱼类识别应用程序（FishSnap），该应用程序将免费向公众开放，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，并与华盛顿特区的国家自然历史博物馆合作开展外展活动，举办关于鱼类生物多样性的新公共展览。最近对鱼类系统发育的研究正在解决关于物种最丰富的海洋鱼类群体之间关系的长期不确定性，并为推断解释其非凡多样性的机制提供了前所未有的机会。该项目利用新发现的鱼类之间的亲缘关系，揭示了底栖和远洋两种独立的进化支，以研究与其生态栖息地相关的基因组和形态特征之间的联系。研究人员将收集并比较蛋白质编码基因的基因组级DNA序列数据集，以推断出这两个群体中约800个物种的系统发育树。这棵树将在精心挑选的化石数据的基础上进行时间校准，为比较研究提供一个有日期的进化框架。该项目还将收集一个大型的表型（数字图像）数据集，用于形态计量学分析。利用最先进的比较方法，该项目将揭示沿底-中上层轴的栖息地变化对形态和谱系多样化速度的影响。将分子系统发育、化石记录、性状和生态数据以及比较方法结合起来，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.