Ultrastructure of Unikaryon nomimoscolexi n. sp. (Microsporida, Unikaryonidae), a parasite of Nomimoscolex sp. (Cestoda, Proteocephalidea) from the gut of Clarotes laticeps (Pisces, Teleostei, Bagridae)

Unikaryon nomimoscolexi n. sp. was examined by electron microscopy from material collected in Senegal (West Africa). It parasitizes adult of Nomimoscolex sp. (Cestoda) from the gut of the freshwater fish Clarotes laticeps. The microsporidium is parasitic in parenchymal cells. All live cycle stages have isolated nuclei. Merogony and sporogony take place in direct contact with the host cell cytoplasm and ultimately give rise to unikaryotic sporoblasts and spores. The sporogony is disporoblastic. The spores are ovoid and measure, in thin sections, 3.43 plus or minus 0.4 x 1.51 plus or minus 0.18 mu m. The polaroplast has an anterior lamellar part and a posterior vesicular part. The polar tube is isofilar and is arranged in 6 to 8 coils.