The family Pseudokeronopsidae Borror & Wicklow, 1983 has an extensive history of iterative revisions regarding phylogenetic relationships of its members and some related taxa from the order Urostylida. The accumulation of morphological and multigene data has provided the opportunity to gain a more comprehensive understanding of their systematic and evolutionary relationship. We conducted phylogenetic analyses of multiple molecular markers and predicted secondary structures of SSU rRNA and ITS regions by adding 14 new sequences. The results demonstrate that: (1) all the present phylogenetic analyses support the transfer of the subfamily Thigmokeronopsinae from the family Pseudokeronopsidae to the family Urostylidae; (2) the monophyly of two subfamilies Pseudokeronopsinae and Nothoholostichinae is substantiated with high support values of the SSU rDNA, LSU rDNA and the concatenated rDNA loci; (3) the monophyly of Pseudokeronopsidae is substantiated of the LSU rDNA only, and the AU tests do not reject the possibilities of Anteholosticha pulchra in this family; (4) phylogenetic trees based on the ITS region do not support the monophylies of the Pseudokeronopsidae and Nothoholostichinae, but the AU tests do not reject their possibilities; and (5) even though Pseudokeronopsis is morphologically well‐defined, it is very likely a paraphyletic genus in which both Antiokeronopsis and Uroleptopsis could be included. Moreover, this study reveals that the V2 and V4 regions of the SSU rRNA molecule are rather conserved at genus level and could be used to distinguish different subfamilies and families. Although they are less stable than the Watson–Crick complementarities, the GU appositions often occur in the ITS transcripts, which are much more variable at genus level than the V2 and V4 regions of the SSU rRNA molecule.

中文翻译：

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基于rDNA的三个有争议的尿嘧啶纤毛虫亚科的系统发育的见解

Pseudokeronopsidae Borror＆Wicklow家族，1983年，关于其成员与Urostylida顺序的一些相关分类群的亲缘关系进行了反复的修订。形态学和多基因数据的积累提供了一个机会，可以更全面地了解它们的系统和进化关系。我们进行了多种分子标记的系统发育分析，并通过添加14个新序列预测了SSU rRNA和ITS区域的二级结构。结果表明：（1）目前所有的系统发育分析都支持拟南芥科的亚科从拟假单胞菌科转移到漆皮科。（2）两个假亚科假单胞菌和鼻甲亚科的单亲属被SSU rDNA，LSU rDNA和级联的rDNA基因座的高支持值所证实；（3）假角膜科的单科仅由LSU rDNA证实，而AU测试并不排除存在的可能性。这个家庭的Anteholosticha pulchra；（4）基于ITS区域的系统发育树不支持假角鲨科和Noholholostichinae的单核，但AU测试并不排除它们的可能性。（5）即使假性角膜病在形态上是明确定义的，也很可能是抗角膜病和尿毒症的共生属可以包括在内。此外，这项研究表明，SSU rRNA分子的V2和V4区在属水平上相当保守，可用于区分不同的亚科和科。尽管它们不像沃森-克里克互补性那样稳定，但GU并置经常出现在ITS转录物中，在属水平上的可变性比SSU rRNA分子的V2和V4区域大得多。