虽然metopids(Armophorea:Metopida)代表了在低氧环境中蓬勃发展的物种最丰富的自由生活的厌氧纤毛虫群,我们对它们真正的多样性的理解仍然不完整。大多数metopid物种仍然仅在形态上进行表征。特别是,所谓的IAC进化枝(过去以包括的一些分类单元命名,Idiometopus,Atopospira,和克利夫兰利达),包括自由生活的成员以及内共生的成员(Clevelandellida命令),非常需要修改。在我们的研究中,我们在IAC进化枝中建立了一个新的自由生活属,匹美多n.根。,描述了两个新物种,P.nanusn.sp.,和P.permonicusn.sp.,使用最新的分子和形态学方法。该属的特征是小细胞(长达75μm),不超过10个肾上腺膜和8个躯体运动,通常,四个长尾纤毛可以变硬。除了形态学和分子特征,我们还对多态物种P.nanusn.sp.进行了统计形态分析。我们讨论了较早的形态学描述物种Metopusminor作为几种长度小于50μm的小型metopid的假定集体分类单元的相关性。
While metopids (Armophorea: Metopida) represent the most species-rich group of free-living anaerobic ciliates thriving in hypoxic environments, our understanding of their true diversity remains incomplete. Most metopid species are still characterized only morphologically. Particularly, the so-called IAC clade (named in the past after some of the taxa included, Idiometopus, Atopospira, and Clevelandellida), comprising free-living members as well as the endosymbiotic ones (order Clevelandellida), is in serious need of revision. In our study, we establish a new free-living genus in the IAC clade, Pidimetopus n. gen., with descriptions of two new species, P. nanus n. sp., and P. permonicus n. sp., using up-to-date molecular and morphologic methods. The genus is characterized by small cells (up to 75 μm long), not more than 10 adoral membranelles and eight somatic kineties, and usually, four long caudal cilia that can stiffen. In addition to morphologic and molecular characterizations, we also conducted a statistical morphotype analysis of the polymorphic species P. nanus n. sp. We discuss the relevance of the earlier morphologically described species Metopus minor as a putative collective taxon for several small metopids less than 50 μm long.