Astome ciliates are a diverse group of obligate endosymbionts, living in the alimentary tract of invertebrates and vertebrates. In the digestive tube of two endogeic lumbricid earthworms, we discovered Metaradiophrya speculorum sp. n. and re-discovered Maupasella mucronata after almost half a century. Their systematic positions were determined using the 18S rRNA gene, ITS1-5.8S-ITS2 region, and the barcoding D1/D2 domains of the 28S rRNA gene. According to the present phylogenetic analyses, astomes isolated from the alimentary tract of endogeic earthworms form a diverse paraphyletic assemblage, whose crown radiation contains species isolated from anecic and epigeic earthworms. The genus Metaradiophrya was depicted as monophyletic in multi-gene analyses and its taxa clustered according to the ecological groups of their host earthworms. The traditional classifications of the genus Metaradiophrya within the family Radiophryidae, which is characterized by a Λ-shaped attachment organelle, was however questioned. Genetic data suggested Metaradiophrya to be closely related to Anoplophrya, which does not possess any holdfast organelles and belongs to the family Anoplophryidae. The genus Maupasella was traditionally classified in the nominotypical family Maupasellidae, which is defined by the presence of a short, apical attachment spine. Interestingly, genetic data suggested that Maupasella represents an “orphan” lineage within the endogeic cluster, with some affinity to Subanoplophrya, which lacks holdfast organelles. Since there is only little correlation between the morphology-based and molecular classifications of astomes, the reconciliation of both frameworks will require accounting for adaptive radiation and host-driven diversification—two phenomena that have very likely shaped the evolution of astomes.

纤毛虫纤毛虫是各种各样的专性内共生菌，生活在无脊椎动物和脊椎动物的消化道中。在两个内生虫的消化管中，我们发现了Metaradiophrya speculorum sp.。。并在将近半个世纪后重新发现了Maupasella mucronata。使用18S rRNA基因，ITS1-5.8S-ITS2区和28S rRNA基因的条形码D1 / D2结构域确定它们的系统位置。根据目前的系统发育分析，从内生earth的消化道中分离出的原子形成了多种生物共生组合，其冠状辐射中含有从风和epi中分离出的物种。radi虫属在多基因分析中被描述为单系的，其分类群根据其寄主earth的生态群进行聚类。然而，人们对放射蝇科中的radi虫属的传统分类提出了质疑，这种分类以“ -”形附着细胞器为特征。遗传数据表明Metaradiophrya是密切相关的Anoplophrya，它不具有任何浩方细胞器和属于家庭Anoplophryidae。传统上，毛帕氏菌属被归类为毛帕氏菌科的非典型家族，其定义是存在一个短而根尖的附件脊柱。有趣的是，遗传数据表明莫帕氏菌代表内吞簇内的“孤儿”谱系，与缺乏固定细胞器的Subanoplophrya有一定亲和力。由于基于形态的原子分类与分子分类之间几乎没有相关性，因此两个框架的协调都需要考虑适应性辐射和宿主驱动的多样化-这两种现象很可能影响了原子的进化。