Luo Xiaotian, Li Lifang, Wang Chundi, Bourland William, Lin Xiaofeng, Hu Xiaozhong
Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China; Department of Biological Sciences, Boise State University, Boise 83725, USA.
Marine College, Shandong University, Weihai 264209, China; Department of Biological Sciences, University of Ulsan, Ulsan 44610, Korea.
Eur J Protistol. 2017 Aug;60:119-133. doi: 10.1016/j.ejop.2017.05.001. Epub 2017 May 17.
Two oxytrichid ciliates, Stylonychia (Metastylonychia) nodulinucleata Shi and Li, 1993 and Gastrostyla steinii Engelmann, 1862; collected from Huguangyan Maar Lake and Shenzhen Mangrove Nature Protection Area, southern China, respectively, were investigated using standard methods. The uncommon species Stylonychia (Metastylonychia) nodulinucleata can be recognized by its large body size, the conspicuous caudal cirri in vivo, and a moniliform macronucleus. We provide the first record of the small subunit ribosomal RNA (SSU rRNA) gene sequence for the species. The division of Stylonychia into two subgenera based on morphological and morphogenetic data is supported by the phylogenetic analyses, in which Stylonychia (Metastylonychia) nodulinucleata is placed as a sister branch to the clade including all the sequences of Stylonychia (Stylonychia) mytilus complex. The first brackish water population of Gastrostyla steinii is described in detail, with emphasis on its morphogenesis, which corresponds well with previous populations. In the phylogenetic trees, all the available Gastrostyla sequences, except for Gastrostyla sp. Y2 (KT780432) (probably a misidentification), nest together in the big group of the subfamily Stylonychinae with moderate to high support (ML/BI, 91%/0.95), very likely revealing the monophyly of the genus Gastrostyla.
分别从中国南方的湖光岩玛珥湖和深圳红树林自然保护区采集了两种尖毛虫类纤毛虫，即1993年Shi和Li发现的结节核原柱毛虫（Stylonychia (Metastylonychia) nodulinucleata）以及1862年Engelmann发现的施氏腹柱虫（Gastrostyla steinii），并采用标准方法对其进行了研究。不常见的结节核原柱毛虫可通过其较大的体型、体内明显的尾纤毛以及念珠状大核来识别。我们提供了该物种小亚基核糖体RNA（SSU rRNA）基因序列的首次记录。基于形态学和形态发生学数据将原柱毛虫分为两个亚属的分类方式得到了系统发育分析的支持，在该分析中，结节核原柱毛虫被置于一个分支中，作为包括原柱毛虫（Stylonychia）贻贝复合体所有序列的进化枝的姐妹分支。详细描述了施氏腹柱虫的首个咸淡水种群，重点是其形态发生，这与之前的种群情况吻合良好。在系统发育树中，除了腹柱虫属物种Y2（KT780432）（可能是误鉴定）外，所有可用的腹柱虫序列在腹柱虫亚科的大群组中聚集在一起，支持度适中至较高（最大似然法/贝叶斯推断，91%/0.95），很可能揭示了腹柱虫属的单系性。
