Abstract

Ascidians (Phylum: Chordata) are sessile and filter-feeding marine animal, species identification of ascidians is possible by observing various morphological and anatomical features in various stages of life span. However, this method is labor intensive, time-consuming and very difficult for non-specialists particularly when dealing with field collections. Suborder Aplousobranchiata and Phlebobranchiata is the largest group of tunicates within, morphological and molecular data suggest that Didemnidae and Ascidiidae are monophyletic, but the monophyly of each genus and their phylogenetic relationships are still poorly understood. Therefore, this study was aimed to develop DNA barcodes of ascidians belonging to the orders of Aplousobranchiata and Phlebobranchiata species namely Diplosoma listerianum, Lissoclinum fragile, Didemnum psammatode, Phallusia fumigata and Phallusia ingeria collected from Andaman and Nicobar Islands were sequenced and submitted in Gen Bank. Colony structure, Scanning Electron Microscope (SEM) for spicules of colonial ascidians, larval type and zooids formation were found to be the most useful morphological characters for discriminating the species. Our BLAST results proved D. Listerianum KP842724 (98%) L. fragile KP842726 (100%) D. psammatode KP779902 (99%), P. fumigata KP779904 (99%) and P. ingeria KP842727 (100%) similarity and this is the first report of mitochondrial COI gene of these ascidians from Andaman and Nicobar Islands. We explored the usefulness of CO1 gene sequences for molecular level identification and mtDNA data in assessing a phylogenetic relationship of ascidian species.

摘要

海鞘（Phylum：Chordata）是无柄和滤食性海洋动物，通过观察生命各个阶段的各种形态和解剖特征，可以鉴定海鞘的物种。但是，这种方法是劳动密集型的，费时的，并且对于非专业人员而言尤其是困难的，特别是在处理田间收集物时。亚目Aplousobranchiata和Phlebobranchiata是其中最大的被膜群，形态和分子数据表明，Didemnidae和Ascidiidae是单系的，但对每个属的单系及其系统发育关系仍知之甚少。因此，本研究旨在开发属于Aplousobranchiata和Phlebobranchiata物种Diplosoma listerianum，对从安达曼和尼科巴群岛收集的脆弱Lissoclinum，Didemnum psammatode，Phallusia fumigata和Phallusia ingeria进行了测序，并提交给Gen Bank。菌落的结构，扫描型电子显微镜（SEM）可以用来鉴定菌落的形态，幼虫的类型和类动物的形成是辨别该物种的最有用的形态特征。我们的BLAST结果证明了李斯特氏菌KP842724（98％）易碎李氏菌KP842726（100％）psammatode菌KP779902（99％），熏蒸疟原虫KP779904（99％）和ING。KP842727（100％）相似，这是来自安达曼和尼科巴群岛的这些海鞘的线粒体COI基因的首次报道。我们探索了CO1基因序列在评估海鞘物种的系统发育关系中对分子水平鉴定和mtDNA数据的有用性。