Gao Feng, Fan Xinpeng, Yi Zhenzhen, Strüder-Kypke Michaela, Song Weibo
Laboratory of Protozoology, Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
Parasitol Int. 2010 Dec;59(4):549-55. doi: 10.1016/j.parint.2010.07.002. Epub 2010 Jul 15.
Many scuticociliates are facultative parasites of aquatic organisms and are among the most problematic ciliate taxa regarding their systematic relationships. The main reason is that most species, especially taxa in the order Thigmotrichida have similar morphology and have not been studied yet using molecular methods. In the present work, two scuticociliate genera, represented by two rare parasitic species, Philasterides armatalis (order Philasterida) and Boveria subcylindrica (order Thigmotrichida), were studied, and phylogenetic trees concerning these two genera were constructed based on their 18 S rRNA gene sequences. The results indicate that: 1) Philasterides forms a sister group with Philaster, supporting the classification that these two genera belong to the family Philasteridae; 2) it is confirmed that the nominal species, Philasterides dicentrarchi Dragesco et al., 1995 should be a junior synonym of Miamiensis avidus as revealed by both previous investigations and the data revealed in the present work; and 3) the poorly known form B. subcylindrica, the only member in the order Thigmotrichida, of which molecular data are available so far, always clusters with Cyclidium glaucoma, a highly specialized scuticociliate, indicating a sister relationship between the orders Thigmotrichida and Pleuronematida.
许多盾纤毛虫是水生生物的兼性寄生虫，并且就其系统发育关系而言，是最具问题的纤毛虫类群之一。主要原因是大多数物种，尤其是触毛目（Thigmotrichida）的类群具有相似的形态，并且尚未使用分子方法进行研究。在本研究中，对以两种罕见寄生物种武装费氏虫（Philasterides armatalis，费氏虫目（Philasterida））和亚圆柱形博韦虫（Boveria subcylindrica，触毛目）为代表的两个盾纤毛虫属进行了研究，并基于它们的18 S rRNA基因序列构建了这两个属的系统发育树。结果表明：1）费氏虫属与费氏虫属形成姐妹群，支持这两个属属于费氏虫科的分类；2）如先前研究和本研究中揭示的数据所示，确认1995年费氏虫属的指名物种费氏虫（Philasterides dicentrarchi Dragesco et al.）应为嗜艾迈阿密虫（Miamiensis avidus）的次异名；3）鲜为人知的亚圆柱形博韦虫，是触毛目中目前唯一有分子数据的成员，总是与高度特化的盾纤毛虫青光眼环虫（Cyclidium glaucoma）聚类，表明触毛目和侧盘目之间存在姐妹关系。
