Parvodinium elpatiewskyi, comb. nov., is a common freshwater dinophyte without intercalary plates and with various spines on hypothecal sutures. However, the taxonomy of the species has had a complex history, and its systematic placement remained unclear. The conserved type of P. elpatiewskyi, comb. nov., illustrated here for the first time using electron microscopy, is an environmental sample. Based on the newly collected material from Berlin (Germany) we provide a morphological description using light and electron microscopy as well as new molecular rRNA sequence data to specify the phylogenetic position of P. elpatiewskyi, comb. nov. This species belongs to Peridiniopsidaceae, more precisely to Parvodinium, which usually possesses two intercalary plates. However, evolutionary inference indicates the loss of such plates in P. elpatiewskyi, comb. nov. Other traits that are of taxonomic importance and have not received enough attention in the past are the large Sd plate converging the second antapical plate and the presence of cellular hypocystal opening during replication.

Parvodinium elpatiewskyi，梳子。nov。是一种常见的淡水生物体，没有inter板，在假想缝合线上有各种刺。但是，该物种的分类学历史很复杂，其系统放置仍不清楚。P. elpatiewskyi梳的保守型。nov。是环境样品，在此首次使用电子显微镜进行了说明。基于从柏林（德国）新收集的材料，我们使用光镜和电子显微镜以及新的分子rRNA序列数据提供了形态学描述，以指定Elpatiewskyi梳的系统发生位置。十一月 该物种属于百里香科，更确切地说，属于小球藻，通常具有两个inter板。然而，进化推断表明在P. elpatiewskyi梳中这种板的损失。十一月 在分类学上很重要并且过去没有得到足够重视的其他特征是会聚第二个前额叶板的大Sd板和复制过程中存在的细胞下囊开放。