The species Metchnikovella dogieli (Paskerova et al. Protistology 10:148–157, 2016) belongs to one of the early diverging microsporidian groups, the metchnikovellids (Microsporidia: Metchnikovellidae). In relation to typical (‘core’) microsporidia, this group is considered primitive. The spores of metchnikovellids have no classical polar sac-anchoring disk complex, no coiled polar tube, no posterior vacuole, and no polaroplast. Instead, they possess a short thick manubrium that expands into a manubrial cistern. These organisms are hyperparasites; they infect gregarines that parasitise marine invertebrates. M. dogieli is a parasite of the archigregarine Selenidium pygospionis (Paskerova et al. Protist 169:826–852, 2018), which parasitises the polychaete Pygospio elegans. This species was discovered in samples collected in the silt littoral zone at the coast of the White Sea, North-West Russia, and was described based on light microscopy. No molecular data are available for this species, and the publicly accessible genomic data for metchnikovellids are limited to two species: M. incurvata Caullery & Mesnil, 1914 and Amphiamblys sp. WSBS2006. In the present study, we applied single-cell genomics methods with whole-genome amplification to perform next-generation sequencing of M. dogieli genomic DNA. We performed a phylogenetic analysis based on the SSU rRNA gene and reconstructed a multigene phylogeny using a concatenated alignment that included 46 conserved single-copy protein domains. The analyses recovered a fully supported clade of metchnikovellids as a basal group to the core microsporidia. Two members of the genus Metchnikovella did not form a clade in our tree. This may indicate that this genus is paraphyletic and requires revision.

Metchnikovella dogieli物种（Paskerova等人Protistology 10：148–157，2016）属于早期散布的微孢子虫群之一，即甲虫（Mechnikovellids）（微孢子虫：Metchnikovellidae）。对于典型的（“核心”）微孢子虫病，该组被认为是原始的。甲轮虫的孢子没有经典的极囊固定盘复合体，没有盘绕的极管，没有后液泡，也没有极膜。取而代之的是，它们拥有一个短而厚的手掌，可以扩展为手掌水箱。这些生物是高寄生虫。它们会感染寄生于海洋无脊椎动物的牛至。M. dogieli是archigregarine的寄生虫Selenidium pygospionis（Paskerova等原生生物169：826-852，2018），其parasitises多毛线虫（Pygospio elegans）。该物种是在俄罗斯西北部白海沿岸淤泥沿海区域收集的样品中发现的，并根据光学显微镜进行了描述。没有分子数据可用于这一物种，和metchnikovellids可公开访问的基因组数据被限制为两种：M. incurvata科勒里-梅尼尔，1914年和Amphiamblys SP。WSBS2006。在本研究中，我们将单细胞基因组学方法与全基因组扩增相结合，以进行犬多毛支原体的下一代测序基因组DNA。我们基于SSU rRNA基因进行了系统发育分析，并使用包括46个保守的单拷贝蛋白质结构域的串联比对重建了多基因系统发育。分析回收了完全支持的甲壳纲进化枝作为核心微孢子虫的基础群。Metchnikovella属的两个成员没有在我们的树上形成分支。这可能表明该属是近亲的，需要修改。