Two species of myxozoan parasites (Myxosporea: Bivalvulida), including a new genus, from Patagonotothen sima (Richardson, 1845) (Pisces: Teleostei) in the southwest Atlantic

A new genus and species of myxozoan parasite, Renispora simae, is described from the gall-bladder of the nototheniid fish Patagonotothen sima (Richardson). Four of 12 fish caught in Stanley harbour in the Falkland Islands in May, 1993 were infected. The new genus is placed in the family Alatosporidae and differs from other genera in this family by the shape of the spore body and the shape and site of adhesion of the membranous extensions to the spore valves. To accommodate the new genus, we propose an amendment to the definition of the family Alatosporidae to include forms with reniform spores. Myxidium baueri Kovaleva & Gaevskaya, 1982 is reported from P. sima for the first time. It was found in the gall-bladder of one of the same 12 fish caught in Stanley harbour.