PEET: Collaborative Research: Monographic Studies of the Hydractinioidea

凯恩斯珊瑚礁是地球上最具生物多样性和生态错综复杂的环境之一，但我们对构成珊瑚礁和栖息在其生态位上的生物的了解是零散的。对于经常与珊瑚礁相关的一大类海洋生物--西尼迪亚纲水母动物，史密森学会的科学家斯蒂芬·凯恩斯和杜克大学的克利福德·坎宁安正在进行专题研究，同时培训新的水生动物分类学专家，并汇编关于这些动物的网络可访问数据库。根据最近的DNA序列证据，重点分类群是钟形科、水龙科和海鞘藻科(或水珊瑚)，这三个在形态上截然不同的水生动物类群分布在世界各地，似乎构成了系统发育上的姊妹类群。尽管淡水九头蛇自从Leeuwenhoek的经典描述以来就广为人知，并被广泛应用于现代细胞生物学研究，但它不典型的是缺乏大多数海洋形式所具有的水母或游泳期特征。作为生活史的一部分，这些变型通常有一个附生或水母阶段以及一个游动或远洋水母阶段；一些种群中的这两个阶段是如此不同，以至于多年来为同一物种创建了不同的命名。这项研究的目标之一是调和这种双重分类，部分是通过使用线粒体DNA序列作为物种亲缘关系的标记或签名。有了合理的系统发育分类，关于生物地理分布、进化起源和多样化速度的问题就可以有利可图地进行研究。研究人员正在与加拿大(皇家安大略博物馆的Dale Calder)和意大利(Lecce大学的Ferdinando Boero)的同事以及其他人合作，研究博物馆标本，培养活生物，添加实地考察的新材料，并培训这些生物分类方面的新专家。学生们将全面参与实地考察和参观博物馆，这是他们整体水生动物系统学培训计划的一部分。形态和分子证据将被整合到专题研究中，包括来自线虫包囊和其他结构的电子显微镜的新的形态特征，以及来自核和线粒体核糖体基因的新的分子证据。特别是，杜克大学正在主办一个水生动物测序设施，该设施将提供来自适当准备的收集的DNA序列数据，目的是识别水生动物，将它们与进化的近亲相结合，并在生活史研究中追踪水母和水母各阶段之间的联系。杜克大学还将主持该项目的数据库部分，纳入新的分子数据，并提供到Boero的12,000个分类学参考文献的电子文件和其他信息资源的链接。

9978086Cairns Coral reefs are among the most biologically diverse and ecologically intricate environments on earth, yet our knowledge of the organisms that constitute the reefs and inhabit their niches is fragmentary. For one major group of marine organisms often associated with reefs, the cnidarian class Hydrozoa, collaborating scientists Stephen Cairns at the Smithsonian Institution and Clifford Cunningham at Duke University are conducting monographic research while training new experts in hydrozoan taxonomy and compiling web accessible databases of information on these animals. The focal taxa are the families Campanularidae, Hydractiniidae and Stylasteridae (or hydrocorals), three morphologically distinct groups of Hydrozoa with worldwide distributions that appear to constitute phylogenetically sister taxa, on the basis of recent DNA sequence evidence. Although the freshwater Hydra is well-known since Leeuwenhoek's classic description, and is extensively used in modern cell biology research, it is atypical in lacking the medusa or swimming stage characteristic of most marine forms. These forms usually have an attached or polyp stage as well as a swimming or pelagic medusa stage as part of the life cycle; so different are the two stages in some groups that different nomenclatures have been created over the years, often for the same species. One of the goals of the research is to reconcile this dual taxonomy, in part by using mitochondrial DNA sequences as markers or signatures of species relatedness. With a sound phylogenetic classification in place, questions about biogeographic distribution, evolutionary origins, and tempo of diversification can be profitably pursued. The investigators are collaborating with colleagues in Canada (Dale Calder at the Royal Ontario Museum) and Italy (Ferdinando Boero at the University of Lecce) and others in studying museum specimens, culturing live organisms, adding new material from field expeditions, and training new experts in the taxonomy of these organisms. Students will participate fully in the field expeditions and museum visits as part of their overall training program in hydrozoan systematics. Morphological and molecular evidence will be integrated into the monographic studies, with new morphological characters from electron microscopy of nematocysts and other structures, and new molecular evidence from nuclear and mitochondrial ribosomal genes. In particular, Duke University is hosting a Hydrozoan Sequencing Facility, which will provide DNA sequence data from properly prepared collections, for purposes of identifying hydrozoans, placing them with evolutionary relatives, and tracking links between polyp and medusa stages in life cycle studies. Duke will also host the databasing component of the project, incorporating the new molecular data and providing links to Boero's electronic file of 12,000 taxonomic references and to other information resources.