Edilson Matos

Henneguya amazonica n.sp. (Myxozoa, Myxobolidae), parasitizing the gills of Crenicichla lepidota Heckel, 1840 (Teleostei, Cichlidae) from Amazon river.

The authors present light and electron microscopical data on a myxosporidian found in the gills of Crenicichla lepidota Heckel, 1840 (Teleostei, Cichlidae) from the Amazon river. Based on the spore morphology, it is concluded that this species belongs to the family Myxobolidae, genus Henneguya, and that it constitutes a new species: Henneguya amazonica n.sp. The fine structure of sporogenesis shows that the development follows, in general, the pattern of this and other genera. Nevertheless, some ultrastructural features are reported for the first time in the genus Henneguya: intercellular bridges between daughter generative cells as well as tubuli arranged in aggregates and dispersed within the capsular matrix. The structure of the trophozoite wall suggests that the species is not highly pathogenic, but, to ascertain the true pathogenicity of the species, further studies are needed.

Ultrastructural studies of Henneguya rhamdia n. sp. (Myxozoa) a parasite from the Amazon teleost fish, Rhamdia quelen (Pimelodidae).

Abstract. Henneguya rhamdia n. sp. is described in the gill filaments of the teleost fish Rhamdia quelen, collected from the Peixe Boi River, State of Pará, Brazil. This myxosporean produced spherical to ellipsoidal plasmodia, up to 300 μm in diameter, which contained developmental stages, including spores. Several dense bodies up to 2 μm in diameter were observed among the spores. The spore body was ellipsoidal (13.1 μm in length, 5.2 μm in width, and 2.5 μm in thickness) and each of the two valves presented a tapering tail (36.9 μm in length). These valves surrounded the binucleated sporoplasm cell and two equal ellipsoidal polar capsules (4.7 × 1.1 μm), which contained 10–11 (rarely 12) polar filament coils. The sporoplasm contained sporoplasmosomes with a laterally eccentric dense structure with a half‐crescent section. Based on the data obtained by electron microscopy and on the host specificity, the spores differed from previously described Henneguya species, mainly in their shape and size, number and arrangement of the polar filament coils, and sporoplasmosome morphology.

Henneguya adherens n. sp. (Myxozoa, Myxosporea), parasite of the Amazonian fish, Acestrorhynchus falcatus.

ABSTRACT. A new species of myxosporean from the gill filaments of the freshwater teleost fish, Acestrorhynchus falcatus collected in the Amazon river is described from light and transmission electron microscope observations. The mature spores (total length 32.3 [30.7–35.1] μ) and all developmental stages were found in the same sporogonic plasmodium. The ellipsoidal spore body consists of 2 unequal shell valves adhering together along the suture lines. Each valve, tapering as a caudal projection, forms a long tail (length 20.5 [18.0–21.7] μm). The tail was surrounded by a homogeneous sheath on its length. The polar capsules measuring 3.1 × 1.2 μm contain 3–4 coils of the polar filament. All surfaces of the immature and mature spores were surrounded by a closely adherent homogenous structural sheath, mainly thicker around the tails. The taxonomic affinities of this parasite to other species are discussed.

Light and electron microscopic study of the myxosporean, Henneguya friderici n. sp. from the Amazonian teleostean fish, Leporinus friderici

A new histozoic species of myxosporean was found to infect the gill filaments, gut, kidney and liver of the freshwater teleost Leporinus friderici, collected from the estuarine region of the Amazon, near the city of Belém, Brazil. The plasmodia show asynchronous development, at any one time composed of mature spores and all sporogonic stages. The ellipsoidal spore body, measuring 10.4 microm long and 5.7 microm wide, consists of 2 equal shell valves adhering together along the straight suture line. Each valve has a caudal process measuring 23.3 microm in length. There are 2 symmetric polar capsules, without intercapsular appendix, measuring 5.0 microm x 2.1 microm, and each has a polar filament with 7-8 coils. In general, ultrastructural details of sporoblast and spore development are in agreement with previously described myxosporeans. Some ultrastructural aspects such as cellular alterations of the pericyte in the different organs infected and characterization of the sporoplasmosomes during the sporoplasm maturation are described. This parasite was studied under light and electron microscope and compared with others species of the genus Henneguya, considering also host specificity. From our observations we propose the creation of a new species, Henneguya friderici n. sp.

Ultrastructural data on the life cycle stages of Myxobolus braziliensis n. sp., parasite of an Amazonian fish

Summary A myxosporidium was found in the gills of Bunocepbalus coracoideus, a freshwater fish from the Amazon River near Belem (Brazil) and studied using light and electron microscopy. Sporogenesis follows the usual pattern known in polysporic myxosporidians, giving rise to dispone pansporoblasts. The plasmodial wall presents a very sinuous outline with projections resembling villosities, unusual for histozoic species. During valvogenesis, one of the valves in the suturai ridge curves inwards and some microtubule bundles differentiate. The sporoplasm contains numerous sporoplasmosomes with unique ultrastructural features. Based on the morphologic aspects and specificity of the host species, we propose the creation of a new species, designated Myxobolus braziliensis n. sp.

Some ultrastructural data on the spore development in a Henneguya sp. parasite of the gill of a Brazilian fish.

A myxosporeanHenneguya sp. was found in the gill filaments of a freshwater fish,Hoplosternum littorale, from the lower Amazon river near Belém, Brazil. Plasmodia were represented by numerous vegetative nuclei, generative cells and sporogony stages. The spore body was ellipsoidal and each valve presented a tapering tail ∼45.2 μm in length. The spores differed from those of previously described species in their shape and size. The developmental stages are described and discussed. This histozoic species is reported to be pathogenic, inducing great mortality in the host.

Fine Structure of the Myxosporean, Henneguya curimata n. sp., Parasite of the Amazonian Fish, Curimata inormata (Teleostei, Curimatidae)

Abstract Henneguya curimata n. sp. (Myxozoa, Myxobolidae) is described from the kidney of the teleost Curimata inormata collected in an estuarine region of the Amazon River, near Belém, Brazil. This myxosporean produces large cysts (0.6–1.2 mm in diam.) that represent plasmodia containing all life cycle stages, including spores. The spore body is ellipsoidal (∼ 16.6 μm in length and ∼ 6.2 μm in width), and each valve presents a tapering tail (∼ 19.1 μm in length). These valves surround the binucleate sporoplasm cell and two ellipsoidal polar capsules located side-by-side at the same level, measuring 6.5 × 1.2 μm each and containing 10–11 coils of the polar filament. On the basis of its host specificity and on data collected by light and electron microscopy, the organism, H. curimata n. sp. is distinguished as a new species. The taxonomic affinities and morphological comparisons with other similar species of the same genus are discussed.

Henneguya malabarica sp. nov. (Myxozoa, Myxobolidae) in the Amazonian fish Hoplias malabaricus

Abstract Henneguya malabarica sp. nov. is described from the Amazonian teleost fish Hoplias malabaricus Boch, 1794, collected from the estuarine region of the Amazon river near Belém, Brazil. Plasmodia were represented by several vegetative nuclei, generative cells, and sporogony stages contained in cyst-like plasmodia. The spore body was ellipsoidal (12.6 μm in length and 4.8×3.6 μm in width) and each valve presented a tapering tail (17.1 μm in length). Thin valves surrounded the binucleate sporoplasm cell and two spherical polar capsules (3.7×1.8 μm) that contain five to six coils of the polar filament. The spore had an iodinophilous vacuole. The basal portion of the spore body of immature and mature spores and the whole surface of the tails were surrounded by a close homogeneous sheath. The prevalence of infection was 6.7% in the fish examined. The spores differed from those of previously described species of Henneguya in their shape, size, spore, and arrangement of the polar-filament coil. The taxonomic affinities of this parasite to other species are discussed.

A new microsporidian parasite, Potaspora morhaphis n. gen., n. sp. (Microsporidia) infecting the Teleostean fish, Potamorhaphis guianensis from the River Amazon. Morphological, ultrastructural and molecular characterization.

A fish-infecting Microsporidia Potaspora morhaphis n. gen., n. sp. found adherent to the wall of the coelomic cavity of the freshwater fish, Potamorhaphis guianensis, from lower Amazon River is described, based on light microscope and ultrastructural characteristics. This microsporidian forms whitish xenomas distinguished by the numerous filiform and anastomosed microvilli. The xenoma was completely filled by several developmental stages. In all of these stages, the nuclei are monokaryotic and develop in direct contact with host cell cytoplasm. The merogonial plasmodium divides by binary fission and the disporoblastic pyriform spores of sporont origin measure 2.8+/-0.3 x 1.5+/-0.2 microm. In mature spores the polar filament was arranged into 9-10 coils in 2 layers. The polaroplast had 2 distinct regions around the manubrium and an electron-dense globule was observed. The small subunit, intergenic space and partial large subunit rRNA gene were sequenced and maximum parsimony analysis placed the microsporidian described here in the clade that includes the genera Kabatana, Microgemma, Spraguea and Tetramicra. The ultrastructural morphology of the xenoma, and the developmental stages including the spores of this microsporidian parasite, as well as the phylogenetic analysis, suggest the erection of a new genus and species.

Light and ultrastructural data on Henneguya testicularis n. sp. (Myxozoa, Myxobolidae), a parasite from the testis of the Amazonian fish Moenkhausia oligolepis

Light and electron microscopical data on a myxosporidian found in the testis of Moenkhausia oligolepis Gunther (Teleostei, Characidae, Tetragonopterinae) from the lower Amazon River near Belém, Brazil, are described. Based on spore morphology, we conclude that this species belongs to the family Myxobolidae and genus Henneguya. Mature spores (total length 27.5 (27.0–28.5) µm) were observed at the periphery of the testis. The ellipsoidal spore body consists of two unequal shell valves adhering together along the suture lines. The spore body is ellipsoidal, 14.0 µm long and 6.5 µm wide. Each valve tapers to a single caudal projection, forming a 13.5 µm long tail (13.0–14.5 µm). The spore is surrounded by a homogenous dense sheath. The polar capsules, measuring 9.0 × 2.0 µm, contain 12–13 coils of the polar filaments. Morphological differences between this material and other species of the genus Henneguya indicated the erection of a new species, which was named H. testicularis. The taxonomic affinities of this parasite are discussed.