LIGHT AND ELECTRON-MICROSCOPIC DESCRIPTION OF POLYSPOROPLASMA NG (MYXOSPOREA, BIVALVULIDA), POLYSPOROPLASMA-SPARIS N-SP FROM SPARUS-AURATA (L) AND POLYSPOROPLASMA-MUGILIS N-SP FROM LIZA-AURATA L

A new myxosporean genus, Polysporoplasma, is erected and named after t he numerous sporoplasms (from 4 to 12) of the spore. Two new species, P. sparis and P. mugilis, found in the teleosteans Sparus aurata and L iza aurata, respectively, are described by light and electron microsco py. They differ in the number of coils of the polar filament, number o f sporoplasms and the thickness/length ratio of the spore. Both specie s are disporous and histozoic in the trunk kidney. Prevalence of infec tion is 18.3% for P. sparis and 14.8% for P. mugilis. Remarkable featu res of both spores are the large size of capsulogenic cells which enve lope sporoplasmic cells, the pierced ornamentation of the valves and t he two posterior bulges at the end of the spore. The taxonomical and b iological implications of the erection of the genus are discussed.