Henneguya paraensis n. sp. (Myxozoa; Myxosporea), a new gill parasite of the Amazonian fish Cichla temensis (Teleostei: Cichlidae): morphological and molecular aspects.

The present study describes light microscopy, transmission electron microscopy, and molecular analyses of a myxosporid found parasitizing the gill region of the teleost fish Cichla temensis, collected from the Tocantins River, near Cametá, Pará State, Brazil. The prevalence of infection was 60 %. The spore-containing cysts that were located in the gill lamellae were oval and whitish. The spores had a mean length of 42.3 ± 0.65 µm; fusiform body, 12.8 ± 0.42-µm long and 8.6 ± 0.32-µm wide; each of the two valves exhibited a tapering tail of 29.5 ± 0.73 µm length. The spores had two polar capsules, 7.4 ± 0.16-µm long by 2.6 ± 0.08-µm wide, containing a polar filament with 5-7 twists. The spores differ from the species previously described, and phylogenetic analysis based on spore morphology and molecular aspects indicated that the fish parasite Henneguya sp. has a strong trend to form clades mainly based on the environment and host order/family. Thus, we conclude that the species belongs to the family Myxobolidae, genus Henneguya, which comprises a new species: Henneguya paraensis n. sp.