This study set out to bolster morphological and molecular datasets of marine gregarine apicomplexans. Gregarines were sampled from the Sea of Japan and Northwest Pacific from cirratuliform polychaetes (Acrocirridae, Cirratulidae, and Flabelligeridae), as well as sipunculids. Trophozoites (feeding stages) were gathered for identification using light microscopy, scanning electron microscopy, and transmission electron microscopy. Cells were also collected for molecular phylogenetic analysis using 18S rDNA and 28S rDNA. As a result, three new species of Selenidium, S. planusae n. sp., S. validusae n. sp., and S. pyroidea n. sp. were described, and additional morphological and genetic data were gathered for an existing species, S. orientale; and Trollidium was established as a new genus. Trollidium akkeshiense n. gen. n. sp. possessed a unique, unsymmetrical organization of microtubules running the longitudinal length of one side of the trophozoite, corresponding to a zig-zag pattern of epicytic (surface) folds, and a flicking pattern of movement. Phylogenetic analyses of 18S rDNA and 28S rDNA showed that these portions of the ribosomal operon are able to resolve some relationships among Selenidium, while other lineages including Trollidium akkeshiense n. gen. n. sp. appeared to be highly influenced by long branch attraction. High evolutionary rates along the ribosomal operon of gregarines may hinder this marker from resolving deeper nodes among early apicomplexans.

这项研究着手加强海洋性人造黄油apicomplexans的形态和分子数据集。从日本海和西北太平洋采集的牛油提取物都来自环状似的多毛类（棘形科，环状和科），以及剑兰。收集滋养体（饲养阶段）以使用光学显微镜，扫描电子显微镜和透射电子显微镜进行鉴定。还使用18S rDNA和28S rDNA收集细胞进行分子系统发育分析。结果，Selenidium的三个新种，S.planusae n。sp。，S.validusae。sp。和S. pyroidea n。sp。进行了描述，并收集了现有物种的其他形态和遗传数据，小号。东方; 和Trollidium被确立为一个新属。Trollidium akkeshiense。gen。。sp。拥有独特的，不对称的微管组织，在滋养体一侧的纵向长度上延伸，对应于上皮（表面）褶皱的锯齿形和运动的甩动型。对18S rDNA和28S rDNA的系统发育分析表明，核糖体操纵子的这些部分能够解决硒的一些关系，而其他谱系（包括Trollidium akkeshiense）。gen。。sp。似乎受长枝吸引的影响很大。沿人造黄油核糖体操纵子的高进化速率可能会阻止该标记物解析早期apicomplexans中的较深节点。