ULTRASTRUCTURE AND DEVELOPMENT OF NEONOSEMOIDES-TILAPIAE (SAKITI AND BOUIX, 1987) NOV-GEN, NOV-COMB (PROTOZOA, MICROSPORA) FROM AFRICAN CICHLID FISH

Neonosemoides tilapiae n.g., n. comb., previously described in Cichlid fish (Sarotherodon melanotheron, Tilapia guineensis and T. zillii) fr om Benin, was found in Tilapia guineensis caught in Senegal and studie d with the electron microscope. All developmental stages were in direc t contact with the host-cell cytoplasm. The life cycle had two merogon ial phases and one sporulation sequence. Nuclei were paired as diploka rya throughout the first merogony and were unpaired throughout the sec ond merogony and the sporogony. Meronts were surrounded by a thin plas ma membrane and their division occurred by binary fission or by plasmo tomy. Sporogonial plasmodia were surrounded by a thick electron-dense wall and divide by multiple fission into numerous uninucleate sporobla sts. Meiosis was not observed. The spores were uninucleate, pyriform a nd had anisofilar polar filament and lamellar polaroplast. A new genus , Neonosemoides, and a new family, Neonosemoidiidae, were created to c ontain this species, which became Neonosemoides tilapiae (Sakiti and B ouix, 1987) n.g., n. comb.