RUI: Phylogeny of the Terebellida and Sabellida (Annelida),and Evolution of Larval Developmental Modes

小行星9806848 本研究项目的目标是破译多毛类环节动物的Teabellida和Sabellida订单之间的进化关系，使历史上的变化模式，在幼虫发育可以在这个群体中进行检查。 该命令Teabellida和Sabellida一起形成一个最多样化的和最有名的多毛类环节动物蠕虫的幼虫发育模式已被很好地表征。 他们提供了一个很好的机会，以解决一些基本的问题，在海洋无脊椎动物的幼虫发育的演变，因为这组蠕虫中发生的喂养（营养型）和非喂养（lecithotrophic）幼虫。 我将使用核（延伸因子-1a和RNA聚合酶II）和线粒体（细胞色素氧化酶I）DNA序列数据来分析的系统发育关系的Teabellida和Sabellida。 绘制的系统发育分析的结果，将推断出的祖先模式的幼虫发育，和lecithotrophy，相反的带间营养，和非metatrochal间营养在整个历史上的组之间的变化的频率和方向将进行检查。 系统发育分析的结果将提供重新分类的Teabellida和Sabellida的基础。 对幼虫发育的性状优化将为了解幼虫发育模式的进化提供新的思路。 如果它表明，对带担轮幼虫的serpulids已从一个祖先，非喂养幼虫的发展推断，然后同源性的担轮幼虫之间的螺旋门，一个字符上的早期动物进化理论的铰链，必须重新评估;如果衍生的营养不良已经在Teabrida和Sabellida中出现了不止一次，则可以支持关于幼虫进食的功能约束导致多重并行的论点。

9806848 McHugh The goal of this research project is to decipher the evolutionary relationships among the polychaete annelid orders Terebellida and Sabellida, so that historical patterns of change in larval development can be examined in this group. The orders Terebellida and Sabellida together form one of the most diverse and best known groups of polychaete annelid worms for which larval developmental modes have been well-characterized. They provide an excellent opportunity to address some fundamental questions regarding the evolution of larval development in marine invertebrates, because both feeding (planktotrophic) and non-feeding (lecithotrophic) larvae occur in this group of worms. I will use nuclear (elongation factor-1a and RNA polymerase II) and mitochondrial (cytochrome oxidase I) DNA sequence data to analyze the phylogenetic relationships of the Terebellida and Sabellida. Drawing on the results of the phylogenetic analyses, the ancestral mode of larval development will be inferred, and the frequency and direction of changes among lecithotrophy, opposed-band planktotrophy, and non-metatrochal planktotrophy throughout the history of the group will be examined. The results of the phylogenetic analysis will provide the basis for a re-classification of the Terebellida and Sabellida. Character optimization on the phylogeny will provide insights into the evolution of larval developmental modes. If it is shown that the opposed-band trochophore of serpulids has been derived from an ancestor for which non-feeding larval development is inferred, then homology of the trochophore among spiralian phyla, a character upon which theories of early animal evolution hinge, must be re-evaluated; if derived planktotrophy has arisen more than once in the Terebellida and Sabellida, then arguments that functional constraints on larval feeding have led to multiple parallelism may be supported.