Description of Myxobolus hoabinhensis n. sp. (Myxosporea: Myxobolidae), infecting the trunk muscles of goldfish Carassius auratus (Linnaeus, 1758) (Cypriniformes: Cyprinidae) in northern Vietnam

During a survey of myxosporean parasites of freshwater fishes in northern Vietnam, myxospores resembling those of the genus Myxobolus (Myxosporea: Myxobolidae) were found in the trunk muscle of 6 out of 35 specimens (17.14%) of wild goldfish Carassius auratus (Cypriniformes: Cyprinidae). The mature spores were 12.0 +/- 0.4 (11.4 - 12.6) mu m long, 8.5 +/- 0.2 (7.9 - 9.0) mu m wide and 6.1 +/- 0.2 (5.8 - 6.3) mu m thick, containing two pyriform-shaped polar capsules unequal in size. The larger polar capsule was 7.6 +/- 0.3 (7.1 - 8.4) mu m long and 3.5 +/- 0.1 (3.3 - 3.8) mu m wide, and the smaller polar capsule was 6.2 +/- 0.3 (5.5 - 6.7) mu m long and 2.9 +/- 0.2 (2.6 - 3.4) mu m wide. Each polar capsule contained a polar filament with 3-5 coils. A phylogenetic analysis based on the small subunit rDNA (SSU rDNA) sequence revealed that this Myxobolus species forms a distinct branch in the phylogenetic tree sister to Myxobolus artus and Myxobolus cyprini, with DNA sequence similarity at 97.6% to M. artus and 97.5% to M. cyprini. A combination of the morphological characteristics and molecular data suggest that this is an undescribed species, and we propose the name Myxobolus hoabinhensis n. sp.

Automated summary

During a survey in northern Vietnam, myxospores resembling Myxobolus genus were found in the trunk muscle of wild goldfish. Phylogenetic analysis suggests that this is a new undescribed species.