Loxocephalids represent a nonmonophyletic assemblage of oligohymenophorean ciliates with morphological features common to both scuticociliates (mode of ontogenesis) and hymenostomes (morphology of the oral structures). In phylogenetic analyses that include both nuclear and mitochondrial molecular markers, relationships among loxocephalid ciliates are still largely unresolved. With the aim to clarify the phylogeny of the controversial order Loxocephalida Jankowski, 1980, we provide the first 18S rRNA gene sequences of three morphologically well-described ciliates currently included in the order, namely Cinetochilum margaritaceum, Zitheron hovassei, and Zitheron muscorum comb. nov. We also provide the first 18S rRNA gene sequence for the monotypic genus Urozona. Here we present improved diagnoses for these species based on updated morphologic data. Our molecular data circumscribe the family Cinetochilidae Perty, 1852 and support the exclusion of genus Cinetochilides from family Cinetochilidae; therefore, we establish a family Cinetochilididae fam. nov. We consider Urozona as incertae sedis in Oligohymenophorea at the current state of knowledge.

Loxocephalids 代表寡膜纤毛虫的非单系组合，其形态特征与鳞状纤毛虫（个体发生方式）和处女膜口（口腔结构的形态）共有。在包括核和线粒体分子标记的系统发育分析中，loxocephalid 纤毛虫之间的关系在很大程度上仍未得到解决。为了阐明有争议的Loxocephalida Jankowski目的系统发育，1980年，我们提供了目前包含在该目中的三种形态学良好描述的纤毛虫的第一个18S rRNA基因序列，即Cinetochilum margaritaceum、Zitheron hovassei和Zitheron muscorum comb。十一月 我们还提供了单型属的第一个 18S rRNA 基因序列乌罗佐那 在这里，我们根据更新的形态学数据对这些物种进行了改进的诊断。我们的分子数据限定了 Cinetochilidae Perty，1852 年，并支持将 Cinetochilides 属从Cinetochilidae 中排除；因此，我们建立了一个家族 Cinetochilididae fam。十一月 在目前的知识水平下，我们认为Urozona是寡膜藻属中的 incertae sedis。