Until now, Hemistasia phaeocysticola was the only representative of the monogeneric family Hemistasiidae available in culture. Here we describe two new axenized hemistasiids isolated from Tokyo Bay, Japan. Like in other diplonemids, cellular organization of these heterotrophic protists is characterized by a distinct apical papilla, a tubular cytopharynx contiguous with a deep flagellar pocket, and a highly branched mitochondrion with lamellar cristae. Both hemistasiids also bear a prominent digestive vacuole, peripheral lacunae, and paraflagellar rods, are highly motile and exhibit diverse morphologies in culture. We argue that significant differences in molecular phylogenetics and ultrastructure between these new species and H. phaeocysticola are on the generic level. Therefore, we have established two new genera within Hemistasiidae – Artemidia gen. n. and Namystynia gen. n. to accommodate Artemidia motanka, sp. n. and Namystynia karyoxenos, sp. n., respectively. A. motanka permanently carries tubular extrusomes, while in N. karyoxenos, they are present only in starving cells. An additional remarkable feature of the latter species is the presence, in both the cytoplasm and the nucleus, of the endosymbiotic rickettsiid Candidatus Sneabacter namystus.

到目前为止，嗜血杆菌（Hemistasia phaeocysticola）是文化中可用的单基因家族血吸虫科的唯一代表。在这里，我们描述了从日本东京湾分离出的两种新的半胱氨酸半胱氨酸。像其他二倍体动物一样，这些异养生物的细胞组成特征是独特的顶端乳头，具有深鞭毛袋的管状细胞咽部和具有层状cr的高度分支的线粒体。两种半寄主类动物也具有突出的消化液泡，外周空洞和鞭毛杆，活动力强并且在培养中表现出多种形态。我们认为，这些新物种和H. phaeocysticola之间的分子系统发育和超微结构的显着差异在通用级别。因此，我们在血吸虫科中建立了两个新属–蒿属。。和Namystynia gen。。容纳Artemidia motanka，sp。。和Namystynia karyoxenos，sp。n。分别 Motanka A.永久性地携带管状挤出物，而在N. karyoxenos中，它们仅存在于饥饿的细胞中。后者物种的附加显着特征是存在下，在细胞质和细胞核中都，内共生rickettsiid的暂定Sneabacter namystus。