Morphology and phylogeny of Coccomyxa bragantinensis n. sp. (Cnidaria: Myxozoa) found parasitising the Coco Sea catfish, Bagre bagre (Siluriformes: Ariidae), captured off the coast of Northern Brazil.

The present study describes Coccomyxa bragantinensis n. sp., which was found parasitising the gallbladder of the Coco Sea catfish, Bagre bagre, captured off Ajuruteua beach, in the region of Bragança in Pará state, northern Brazil. Most (77.5%) of the 40 fish specimens examined (31/40) had myxospores floating in the bile liquid. These spores are partially ellipsoid, with a tapering anterior extremity and a rounded, elongated posterior extremity with a single piriform polar capsule containing a helicoidal polar filament, with 5-6 coils. A partial sequence of 957 bp of the SSU rDNA gene was obtained from the specimens and deposited in GenBank (xxx). The new species described here - Coccomyxa bragantinensis n. sp. - is phylogenetically similar to Coccomyxa morovi, although it differs from all the other Coccomyxa species and is the first species of this genus to be described from Brazil on the basis of molecular evidence.

Myxobolus sp. and Henneguya sp. (Cnidaria: Myxobolidae) natural co-infection in the kidney of Piaractus mesopotamicus (Characiformes: Serrasalmidae).

This study evaluated the myxozoan infection and histopathology of the kidney of freshwater fish Piaractus mesopotamicus from intensive fish farming in Brazil. A total of 55 fish were examined for myxozoan infection. Infected organs were processed by usual histology and stained with hematoxylin-eosin (H&E) and Ziehl-Neelsen (ZN). From the total of 55 fish analyzed, 47 (85.45%) presented myxospores, being 9.09% (5/55) only with Myxobolus sp., 5.45% (3/55) only with Henneguya sp., and 70.91% (39/55) presenting both parasites. The presence of myxospores was associated with histological alterations in both stromal and renal parenchyma. Myxospores were found mostly in the peritubular interstitial tissue and in low intensity in the glomerulus which caused nuclear hypertrophy and loss of Bowman space. An increase in the glomerular tuft and a reduction in the lumen of the collector tubules were also observed, besides the high number of melanomacrophage cells in the glomerulus. This study reports for the first time detection of myxozoan mixed infection in one organ of pacu and discuss the possible transportation of myxospores in the circulating blood.

Atuais conhecimentos sobre Myxosporea (Myxozoa), parasitas de peixes. Um estágio alternativo dos parasitas no Brasil / Recent information on the Myxosporean (Myxozoa) fish parasites. An alternate stage of the parasites in Brazil

Os autores relatam as recentes informaçöes sobre o ciclo alternativo dos mixosporeos (Myxozoa) comprovados nos últimos anos nos oligoquetas, estimulando pesquisas para estudar o desenvolvimento das numerosas espécies de parasitas de peixes conhecidos e desconhecidos dos mixosporeos no Brasil. Ao mesmo tempo, formas de actinosporeos, raabeia, eliminados pelos oligoquetas da família Ocnerodrilidae, foram relatadas pela primeira vez no Brasil