PurSUiT: Biodiversity and Taxonomy of Fish-Parasitic Gnathiid Isopods on Coral Reefs

长期以来，海洋科学家和公众一直被肉眼容易看到的大型海洋生物所吸引。然而，科学家们越来越意识到大部分在幕后活动的少数海洋生物的重要性。这一类群包括寄生虫，统称为隐动物群。Gnathiid等足类（gnathiids）是一组独特的海洋环境寄生虫，在所有海洋和深海中都有发现。啮齿虫附着在鱼身上，吸食血液，然后脱落，它们在海洋中相当于陆地上的蜱虫和蚊子。有些甚至将血液寄生虫传播给鱼类，就像蜱虫和蚊子传播给鸟类和哺乳动物一样。这个项目的重点是珊瑚礁系统中颌目等足类动物的多样性，这是地球上最多样化的生态系统。该项目是一项国际合作，涉及世界上几乎所有活跃的gnathiid研究人员，他们对该项目进行了大量投资，包括帮助培训美国学生。虽然全世界有数百个研究团队在研究蜱虫和蚊子，但只有少数科学家研究它们的海洋同类——牙颌类等足类动物。因此，虽然可能有数百种gnathiids，但我们只知道其中几种的身份和名称。识别和描述gnathiids的种类是很重要的，因为我们需要了解不同蜱虫或蚊子的种类——即使它们有某些相似之处，它们之间也有重要的差异，比如它们可能传播什么疾病，如果有的话。鉴于gnathiid等足类鱼与蜱虫的相互作用以及蚊子与人类和其他陆地动物的相互作用的相似性，该研究将为理解与陆地系统相比，珊瑚鱼中宿主-寄生虫相互作用和疾病传播的异同提供基础。该项目将有助于教育和培训下一代分类学家和系统学家，并将提高公众对美国和国外珊瑚礁生物多样性的了解。本项目的具体目标是：1)研究热带珊瑚礁及其邻近生态系统中颌目等足类生物多样性、生物地理特征和关键功能特征；2)为尽可能多的物种生成DNA条形码，构建基于分子的系统发育；3)对学生进行颌目等足类分类和系统分类方面的培训。我们将与包括野外生态学家、分类学家、分子生物学家、生物信息学家和博物馆专家在内的国际合作小组合作，采用综合和跨学科的方法。我们将使用我们团队几十年来开发的各种收集技术从具有代表性的珊瑚礁栖息地取样，并将使用最先进的分类学，分子和生物信息学技术来描述和识别gnathiid物种。通过这种方法，我们将填补生物多样性知识的主要空白：1)对具有进化独特性和全球濒危特征的地区进行彻底和系统的采样，因此可能包含未知的gathiid多样性；2)提供鱼寄生类等足类的系统学、生物地理学和遗传多样性的信息，这将使我们对它们的系统发育关系的理解取得重大进展。通过确定寄主利用模式，并将寄生虫生活史阶段联系起来，我们将回答有关寄生等足类动物生态功能的基本问题，并建立解决更复杂的生态和进化问题的能力。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Marine scientists and members of the public have long been drawn to the larger marine organisms easily seen with the unaided human eye. However, scientists are becoming increasingly aware of the importance of the smaller majority of marine life that operate largely behind the scenes. Collectively referred to as cryptofauna this group includes parasites. Gnathiid isopods (gnathiids) are a group of parasites that are unique to marine environments and are found in all oceans and depths. By attaching to fish, extracting blood meals and then dropping off, gnathiids are the marine equivalent of ticks and mosquitos on land. Some even transmit blood parasites to fish just as ticks and mosquitos do to birds and mammals. This project focuses on the diversity of gnathiid isopods in coral reef systems, the most diverse ecological systems on the planet. The project is an international collaboration involving nearly all the active gnathiid researchers in the world who are making significant investments in the project, including helping to train US students. While there are hundreds of research teams worldwide who study ticks and mosquitos, only a handful of scientists study their marine equivalent – gnathiid isopods. As a consequence, while there are likely hundreds of species of gnathiids, we only have identifications and names for a few. Identifying and characterizing gnathiids to species is important for the same reason that we need to know one tick or mosquito species from another – even though they have certain similarities, there are important differences among them, such as what, if any diseases they may transmit. Given the similarity of gnathiid isopod-fish interactions to ticks and mosquito interactions with humans and other land animals, this study will provide the basis for understanding similarities and differences of host-parasite interactions and disease transmission in coral reef fish as compared to terrestrial systems. The project will contribute to educating and training the next generation of taxonomists and systematists, and will improve public understanding of coral reef biodiversity both in the US and abroad.The specific goals of this project are to: 1) Characterize gnathiid isopod diversity, biogeography, and key functional traits in tropical coral reef and adjacent ecosystems; 2) Generate DNA barcodes for as many species as possible and construct a molecular-based phylogeny; and 3) Provide student training in gnathiid isopod taxonomy and systematics. With an international group of collaborators that include field ecologists, taxonomists, molecular biologists, bioinformaticians, and museum specialists, we will use an integrative and interdisciplinary approach. We will sample from representative coral reef habitats using a variety of collecting techniques our team has developed over decades, and will use state of the art taxonomic, molecular, and bioinformatic techniques to describe and identify gnathiid species. Through this approach we will fill major gaps in biodiversity knowledge by: 1) Thorough and systematic sampling of regions characterized as evolutionarily distinct and globally endangered and therefore likely harboring unknown gathiid diversity; and 2) Providing information on the systematics, biogeography and genetic diversity of fish-parasitic gnathiid isopods that will enable major advances in our understanding of their phylogenetic relationships. By identifying patterns of host exploitation, and linking parasite life history stages, we will answer fundamental questions regarding ecological function of parasitic isopods and build capacity to address more sophisticated ecological and evolutionary questions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.