Molecular and Morphological Redescriptions of Enteric Myxozoans, Enteromyxum leei (formerly Myxidium sp. TP) and Enteromyxum fugu comb. n. (syn. Myxidium fugu) from Cultured Tiger Puffer

Abstract

The phylogenies of two enteric myxozoans, Myxidium fugu and Myxidium sp. TP, from cultured tiger puffer Takifugu rubripes were re-evaluated based on their small subunit ribosomal RNA (SSU rRNA) gene sequence and spore morphology. Phylogenetic analysis shows that M. fugu and Myxidium sp. TP are grouped with Enteromyxum species as a monophyletic clade, not with other Myxidium spp. It was also illustrated that spores of M. fugu satisfy the criteria for the genus Enteromyxum for spore morphology. SSU rRNA gene sequence of Myxidium sp. TP shared 99.6% identity to that of Enteromyxum leei. Experimental transmission of Myxidium sp. TP to red sea bream Pagrus major induced the formation of mature spores, which were indistinguishable from those of E. leei in morphology and morphometrics. Myxidium sp. TP is identified as E. leei, and M. fugu is reassigned as Enteromyxum fugu comb. n.