迄今为止编目的微孢子虫多样性已经导致了几个分类群的发展，其中之一是Enterocytozoonida - 一组广义的“终极机会主义者”，感染了许多养殖鱼类和动物，并感染了包括人在内的广泛寄主类群。在这项研究中，我们提供了系统发育、超微结构、发育和病理学证据，以创建一个新的属和种，以持有Jonah蟹（Cancer borealis）的微孢子虫寄生虫。Cancer borealis代表了商业利益的物种，已成为美国和加拿大大西洋海岸新开发的渔业的目标。发现这个物种寄生有一个在肝胰腺α和β细胞的细胞质中发展的微孢子虫寄生虫。我们检索到了一段937bp的寄生虫SSU区域，以及发展和超微结构数据，表明这个物种与Parahepatospora carcini的相似度约为87％，并以与宿主细胞细胞质的直接联系方式进行类似的发展。成熟的孢子呈卵形，长1.48 ± 0.15 µm（SD），宽1.00 ± 0.11 µm（SD）。在系统发育上，新的寄生虫群落位于Enterocytozoonida的同一支线上，与P. carcini相同。我们提供了一个新的属和种来持有寄生虫：伪肝孢子虫北方n. gen. n. sp.（微孢子虫：Enterocytozoonida），并探讨这种物种可能适合于Hepatoporidae家族。 版权所有©2023作者。 Elsevier Inc.发表。保留所有权利。

The microsporidian diversity catalogued so far has resulted in the development of several taxonomic groups, one of which is the Enterocytozoonida - a group of generalist 'ultimate opportunists', which infect many fished and aquacultured animals, as well as a broad suite of host taxa, including humans. In this study, we provide phylogenetic, ultrastructural, developmental, and pathological evidence for the creation of a new genus and species to hold a microsporidian parasite of the Jonah crab, Cancer borealis. Cancer borealis represents a species of commercial interest and has become the target of a recently developed fishery on the USA and Canadian Atlantic coast. This species was found to harbour a microsporidian parasite that develops in the cytoplasm of alpha and beta cells of the hepatopancreas. We retrieved a 937 bp fragment of the parasite SSU region, alongside developmental and ultrastructural data that suggests this species is ∼ 87 % similar to Parahepatospora carcini and develops in a similar manner in direct association with the host cell cytoplasm. The mature spores are ovoid in shape and measure 1.48 ± 0.15 µm (SD) in length and 1.00 ± 0.11 µm (SD) in width. Phylogenetically, the new parasite clades in the Enterocytozoonida on the same branch as P. carcini. We provide a new genus and species to hold the parasite: Pseudohepatospora borealis n. gen. n. sp. (Microsporidia: Enterocytozoonida) and explore the likelihood that this species may fit into the Hepatoporidae family.Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.