Morphological and molecular characterization of parasite Henneguya dugarovi sp. nov. (Myxozoa) from common carp Cyprinus carpio.

A new myxozoan species, Henneguya dugarovi sp. nov., was observed in the gills of Amur common carp Cyprinus carpio haematopterus Martens, 1846 (subspecies of common carp), which inhabits the Lake Baikal basin. The parasite was studied on the basis of spore morphology and molecular methods. Cysts were located intralamellarly in the secondary lamellae. Mature spores of H. dugarovi sp. nov. are symmetrical, with 2 unequal caudal appendages, the spore body is obovate in frontal view and lemon-shaped in lateral view. The spores have a total length of 24-42 μm, a mean ± SD body length of 11.7 ± 0.8 μm (range 10.0-13.1 μm), a width of 8.8 ± 0.5 (7.8-10.2) μm and thickness of 7.3 ± 0.5 (5.8-8.0) μm. Two equal polar capsules are pear-shaped, blunt at the posterior end, narrowed anteriorly and widely spaced, 5.3 ± 0.4 (4.4-6.0) μm long and 3.1 ± 0.3 (2.4-4.0) μm wide. Polar tubules are coiled in 7 turns. The infection rate of H. dugarovi sp. nov. was 56%. Phylogenetic analyses showed that this species is grouped with myxosporeans infecting common carp.