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

A species not identifiable with any of the about 23 Myxobolus species recorded 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 pond farms in Hungary. The strictly tissue-specific plasmodia of the parasite were located, surrounded by hyaline cartilage cells, in the chondrous substance of the terminal parts of the gill arches and in the cartilage structure ventrally connecting the gill arches. The spores of the parasite described as Myxobolus intrachondrealis sp. n. developed in globular or ellipsoidal plasmodia measuring 300-600 microm. By their elongated ellipsoidal shape and similarly elongated polar capsules the spores were well distinguishable from the hitherto described Myxobolus species parasitic in the common carp and also from the cartilage-parasitic Myxobolus species of other fishes.