Myxobolus intrachondrealis sp n. (Myxosporea : Myxobolidae), a parasite ofthe gill cartilage of the common carp, Cyprinus carpio

A species not identifiable with any of the about 23 Myxobolus species recor ded from the common carp so far, was detected in the gills of one- and two- summer-old specimens of the common carp (Cyprinus carpio L.) cultured in po nd farms in Hungary. The strictly tissue-specific plasmodia of the parasite were located, surrounded by hyaline cartilage cells, in the chondrous subs tance of the terminal parts of the gill arches and in the cartilage structu re ventrally connecting the gill arches. The spores of the parasite describ ed as Myxobolus intrachondrealis sp. n. developed in globular or ellipsoida l plasmodia measuring 300-600 mu m. By their elongated ellipsoidal shape an d similarly elongated polar capsules the spores were well distinguishable f rom the hitherto described Myxobolus species parasitic in the common carp a nd also from the cartilage-parasitic Myxobolus species of other fishes.