Qu Zhishuai, Pan Hongbo, Gong Jun, Wang Congcong, Filker Sabine, Hu Xiaozhong
State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen 361104, China.
Engineering Research Center of Environmental DNA and Ecological Water Health Assessment, Shanghai Ocean University, Shanghai 201306, China.
Microorganisms. 2022 Jun 30;10(7):1325. doi: 10.3390/microorganisms10071325.
The subclass Cyrtophoria are a group of morphologically specialized ciliates which mainly inhabit soil, freshwater, brackish water, and marine environments. In this study, we revise more than 50 publications on the taxonomy, phylogeny, and ecology of cyrtophorian ciliates in China since the first publication in 1925, most of which were carried out in coastal areas. The research history can be divided into three periods: the early stage, the Tibet stage, and the molecular stage. To date, 103 morpho-species (147 isolates) have been formally recorded in China, with ciliature patterns described for 82 of them. A species checklist and an illustrated identification key to the genera are provided. A total of 100 small subunit rDNA sequences have been obtained for 74 taxonomic hits (lowest taxonomic rank to species or genus). These sequences are used for the study of molecular phylogeny. Based on these morphological data and molecular phylogeny analyses, we synthesize the understanding of the phylogeny of cyrtophorian ciliates. We hypothesize that the key evolutionary event of cyrtophorian ciliates lies in the separation of the stomatogenesis zone (postoral kineties) from the left kineties, namely, the formation of an independent "sexual organelle". We, furthermore, briefly summarize the ecological features of cyrtophorian ciliates and provide a comprehensive bibliography of related research from China. Finally, we give an outlook on the future research directions of these taxa.
Cyrtophoria亚纲是一类形态特殊的纤毛虫，主要栖息于土壤、淡水、咸淡水和海洋环境中。在本研究中，我们梳理了自1925年首次发表以来，中国关于 Cyrtophoria亚纲纤毛虫分类学、系统发育学和生态学的50多篇出版物，其中大部分研究是在沿海地区开展的。研究历史可分为三个阶段：早期阶段、西藏阶段和分子阶段。截至目前，中国已正式记录了103个形态种（147个分离株），其中82个描述了纤毛模式。提供了一份物种清单和一个属的图示鉴定检索表。共获得了74个分类单元（最低分类等级为种或属）的100个小亚基rDNA序列。这些序列用于分子系统发育研究。基于这些形态学数据和分子系统发育分析，我们综合了对 Cyrtophoria亚纲纤毛虫系统发育的认识。我们推测 Cyrtophoria亚纲纤毛虫的关键进化事件在于口器发生区（口后动基列）与左侧动基列的分离，即形成一个独立的“性细胞器”。此外，我们简要总结了 Cyrtophoria亚纲纤毛虫的生态特征，并提供了中国相关研究的综合参考文献目录。最后，我们展望了这些类群未来的研究方向。
