Quahog Parasite Unknown (QPX) is a facultative parasite of the hard clam, Mercenaria mercenaria. Although it has been observed in clams since the 1960’s and cultivated since the 1990’s, conflicting reports on important aspects of its biology have prevented its formal description. 18S rRNA gene sequences identify QPX as a thraustochytrid, but its production of copious mucus is atypical for this group. There are also conflicting reports about whether QPX shares common features of thraustochytrids, such as the production of an ectoplasmic net and biflagellate zoospores. This study reaffirms the previous descriptions of zoospore production by QPX in culture, in multiple strains from several geographic locations, and provides detail on how to maintain QPX cultures under conditions that promote the production of zoospores. Furthermore, we describe new aspects of the life cycle not previously observed. Finally, we erect Mucochytrium quahogii gen. nov., sp. nov. to accommodate this unusual thraustochytrid.

Quahog未知寄生虫（QPX）是硬c Mercenaria mercenaria的兼性寄生虫。尽管自1960年代以来在蛤中就已经观察到它，并且自1990年代以来就开始养殖它，但有关其生物学重要方面的报道相互矛盾，阻止了对其的正式描述。18S rRNA基因序列将QPX鉴定为破囊壶菌，但该群体大量粘液的产生对于该人群而言是非典型的。关于QPX是否具有破囊壶菌的共同特征，例如胞质网和双鞭毛游动孢子的产生，也有相互矛盾的报道。这项研究重申了QPX在多个地理位置的多种菌株中通过培养产生游动孢子的描述，并详细介绍了如何在促进游动孢子产生的条件下维持QPX培养。此外，我们描述了以前未曾观察到的生命周期的新方面。最后，我们架设Mucochytrium quahogii根。十一月，sp。十一月 以适应这种不寻常的破囊壶菌。