Boise State University, Department of Biological Sciences, Boise, Idaho 83725-1515, USA.
Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic.
Protist. 2020 Jul;171(3):125740. doi: 10.1016/j.protis.2020.125740. Epub 2020 May 30.
We report the discovery of three new species of freshwater metopid ciliates, Pileometopus lynni gen. et sp. nov., Castula flexibilis gen. et sp. nov., and Longitaenia australis gen. et sp. nov. Based on morphologic features and the 18S rRNA gene phylogeny, we transfer two known species of Metopus to the new genus Castula, as C. fusca (Kahl, 1927) comb. nov. and C. setosa (Kahl, 1927) comb. nov. and another known species is herein transferred to the new genus Longitaenia, as L. gibba (Kahl, 1927) comb. nov. Pileometopus is characterized by a turbinate body shape, a dorsal field of densely spaced dikinetids, a bipartite paroral membrane, and long caudal cilia. A distinctive morphologic feature of Castula species is long setae arising over the posterior third of the body (as opposed to a terminal tuft). Longitaenia spp. are characterized by an equatorial cytostome and long perizonal ciliary stripe relative to the cell length. Based on phylogenetic analyses of 18S rRNA gene sequences, we identify and briefly discuss strongly supported clades and intraspecific genetic polymorphism within the order Metopida.
我们报告了三种新的淡水膜口目纤毛虫的发现，即 Pileometopus lynni 属和种新种、Castula flexibilis 属和种新种以及 Longitaenia australis 属和种新种。基于形态特征和 18S rRNA 基因系统发育，我们将两个已知的 Metopus 种转移到新的 Castula 属中，即 C. fusca（Kahl，1927）组合新种和 C. setosa（Kahl，1927）组合新种，另一个已知的种被转移到新的 Longitaenia 属中，即 L. gibba（Kahl，1927）组合新种。Pileometopus 的特征是陀螺形的体型、密集分布的双联体背区、二分的口围膜和长的尾纤毛。Castula 种的一个独特形态特征是长的刚毛从身体的后三分之一处生出（而不是末端丛）。Longitaenia 种的特征是相对于细胞长度具有赤道口和长的周纤毛带。基于 18S rRNA 基因序列的系统发育分析，我们鉴定并简要讨论了膜口目内强烈支持的分支和种内遗传多态性。
