Ministeria vibrans (Filasterea) is a tiny amoeboid species described by Tong in 1997. It has been sporadically found in different habitats, and cultured strains were established. M. vibrans is well characterised by molecular phylogeny but until now was not ultrastructurally investigated in detail. Here, we provide the ultrastructure for this species based on a new strain isolated from oxygen-depleted water of the Baltic Sea. A thin vibrating flagellum could be observed but no vibrating movement of the cell body and no stalk. Our first ultrastructural study of a filasterean taxon revealed radial microvilli supported by bundles of microfilaments. Two centrioles located in the nuclear pit can migrate to the cell periphery and transform into the kinetid: the centriole orthogonal to the kinetosome with a fibrillar root and a basal foot that initiates microtubules. Microvilli in Ministeria suggest their presence in the common ancestor of Filasterea and Choanoflagellata. The kinetid structure of Ministeria is similar to that of the choanocytes of the most deep-branching sponges, differing essentially from the kinetid of choanoflagellates. Thus, kinetid and microvilli of Ministeria illustrate features of the common ancestor of three holozoan groups: Filasterea, Metazoa and Choanoflagellata.

唐氏囊虫（Filasterea）是Tong在1997年描述的一种微小的变形虫物种。它是在不同的生境中偶然发现的，并建立了培养菌株。弧菌具有良好的分子系统发育特征，但到目前为止尚未进行超微结构的详细研究。在这里，我们基于从波罗的海的贫氧水中分离出的新菌株为该物种提供了超微结构。可以观察到薄的振动鞭毛，但是细胞体没有振动运动，也没有茎。我们对丝紫杉分类群的首次超微结构研究显示，微丝束支撑着放射状微绒毛。位于核坑中的两个中心粒可以迁移到细胞外围并转化为类肌体：与原核小体正交的中心基团具有纤维状的根和引发微管的基足。微绒毛Ministeria建议他们在Filasterea和领鞭毛虫的共同祖先存在。的人形结构部长病类似于最深分支的海绵的软骨细胞，本质上不同于鞭毛鞭毛的肌动蛋白。因此，部长病的单核和微绒毛说明了三个整体类的共同祖先的特征：Filasterea，Metazoa和Choanoflagellata。