Glugea vincentiae n. sp. (Microsporidia: Glugeidae) infecting the Australian marine fish Vincentia conspersa (Teleostei: Apogonidae).

Abstract

A parasite of the marine fish Vincentia conspersa was examined by light microscopy and transmission electron microscopy. This parasite develops in the subcutaneous tissue of the body and fins, forming spherical xenomas about 1-2 mm in diameter surrounded by a layer of amorphous material. The observed characteristics of the new parasite are in line with those of the other Glugea species; merogony takes place in the outer zone of the cytoplasm of the host cell, sporogony takes place in sporophorous vesicles, and mature spores are located in the central part of the xenoma. Meronts were cylindrical uninucleate or occasionally triradiate multinucleate, with plasmodia in direct contact with the host cytoplasm. Sporogonic plasmodia divided by multiple cleavage to produce sporoblast mother cells, which after binary fission became sporoblasts. Two types of spores were recognized, both uninucleate, i.e., ovoid or slightly ovoid microspores with a mean size of 5.1 x 2.2 microm and much less frequent as elongated oval macrospores with a mean size of 8.9 x 3.1 microm. The polar tube has between 12 and 14 coils arranged in 1, 2, or 3 layers. Taken together, these characteristics suggest that this microsporidian infecting V. conspersa is a new species of Glugea, which we have named Glugea vincentiae.