Host-Parasite Interaction and Phylogenetic of a New Cnidarian Myxosporean (Endocnidozoa: Myxobolidae) Infecting a Valuative Commercialized Ornamental Fish from Pantanal Wetland Biome, Brazil.

Myxozoans are a diverse group of parasitic cnidarians of wide distribution. A new species, Myxobolus matogrossoensis n. sp., is herein described infecting wild specimens of tetra mato-grosso Hyphessobrycon eques, caught in the Pantanal biome, the world's largest tropical wetland area. Cysts were found in 3 of the 30 examined fishes. Mature myxospores were ovoid in shape in frontal and measured 6.6 ± 0.4 µm (6.2-7.0 µm) in length and 3.5 ± 0.2 µm (3.3-3.7 µm) in width. The two polar capsules were elongated in shape, equal in size and occupying almost half of the myxospore body. They measured 3.3 ± 0.2 µm (3.1-3.5 µm) in length and 1.8 ± 0.1 µm (1.7-1.9 µm) in width. The polar tubules presented three to four turns. Phylogenetic analysis placed the new species within a clade containing myxobolid species from South American characiforms fish and appears as a close species of Myxobolus piraputangae and Myxobolus umidus. Nevertheless, the sequences of the new species and P. umidus and P. piraputangae have a large genetic divergence of 12 and 12.2% in their 18S rDNA gene, respectively. To the best of our knowledge, this is the first report of a Myxobolus species parasitizing the tetra fish mato-grosso, thus increasing our knowledge of cnidarian myxosporean diversity from South America.

Taxonomy and 18S rDNA-based phylogeny of Henneguya multiradiatus n. sp. (Cnidaria: Myxobolidae) a parasite of Brochis multiradiatus from Peruvian Amazon.

A new myxozoan species belonging to the genus Henneguya was isolated from the serous membrane of the visceral cavity of the hognosed catfish Brochis multiradiatus from Peruvian Amazon. Whitish plasmodia, macroscopically visible, were found in four of the thirty examined fishes. Mature myxospores were ellipsoidal in shape in frontal view and had a total length of 44.5 ± 0.6 µm (43.9-45.1), spore body measured 18.7 ± 0.9 µm (16.8-19.6) in length, 7.1 ± 0.2 µm (6.6-7.4) in width and 5.5 ± 0.3 µm (4.9-5.6) in thickness. The two polar capsules were elongated and equal in size, measuring 9.1 ± 0.1 µm (8.8-9.4) in length and 1.7 ± 0.1 µm (1.6-1.8) in width, occupying half of the myxospore body. Polar tubules coiled in 10-11 turns perpendicular to the long axis of the polar capsule. The caudal appendage was not bifurcated and measured 25.8 ± 0.6 µm (24.7-26.5) in length. The sequencing of the 18S rDNA gene resulted in 1400 bp and this sequence did not match any of the myxozoans available in GenBank. Phylogenetic analysis placed the new species in a well-supported subclade of Henneguya spp. infecting callichthyid fishes, with Henneguya loretoensis being the closest species. This study is the first description of a myxozoan species, Henneguya multiradiatus n. sp. from a fish of the genus Brochis.

Molecular Phylogeny and taxonomy of a new Myxobolus species from the endangered ornamental fish, Otocinclus cocama endemic to Peru: A host-parasite coextinction approach.

A new Myxobolus species is described infecting gill filaments of the endangered ornamental fish Otocinclus cocama from Peruvian Amazon. In a total of 35 fish examined, five (14.3%) had myxozoan plasmodia. Taxonomic analysis was performed integrating multiple characters, including morphometrical, biological traits, ssrDNA sequence data and host ecological characters. Myxospores of M. iquitoensis n. sp. were ovoid in shape from the frontal view and measured 17.6±1.2 µm (16.2-19.8 µm) in length and 10.5±0.7 µm (9.8-12 µm) in width. The two polar capsules were elongate in shape, equal in size and occupying almost half of the myxospore body. They measured 8.7±0.4 µm (6.9-9.3 µm) in length and 3.3±0.2 µm (3-3.6 µm) in width. The polar tubules presented six to seven turns. Molecular phylogenetic analysis revealed that the obtained ssrDNA sequence did not match any existing sequences in GenBank but showed M. iquitoensis n. sp. to be a close species of M. figueirae. Nonetheless, the ssrDNA sequences of those species show large genetic divergence. This is the first description and phylogenetic study of a myxozoan parasitizing fish of the genus Otocinclus from South America, as well the first report of these parasites infecting a fish belonging to the Loricariidae family from Amazon basin. Considering the endangered status of the host, the high degree of host-specificity of freshwater histozoic myxobolids, the low occurrence shown by the new myxozoan, and the fact that this is the only host known for this myxozoan, the conservation status of the new species of myxozoan is likely to be connected to the future survival of its host.

A new Myxidium species (Myxozoa: Myxosporea) infecting the gallbladder of the turtle Podocnemis unifilis (Testudines: Podocnemididae) from Peruvian Amazon.

A new myxosporean species, Myxidium peruviensis n. sp., is described parasitizing the gall bladder of the yellow-spotted river turtle Podocnemis unifilis kept in captivity in an Amazonian Peruvian turtle rescue unit in the city of Iquitos, State of Loreto, Peru. The parasite was found in four of ten (40%) P. unifilis examined. The new species was characterized based on morphological and molecular phylogeny analyses. SSU rDNA sequence of the spores of M. peruviensis n. sp. resulted in 1876 nucleotides and this sequence did no match any of the Myxozoa available in the GenBank. Phylogenetic analysis identified the new species as a sister species of Myxidium turturibus, the unique Myxidium species described in a Neotropical turtle. Nevertheless, the SSU rDNA sequences of the new species and M. turturibus have only a 91.5% similarity. This is the first description and molecular study of a Myxozoa in a reptile from Peru. Considering the status of P. unifilis as vulnerable species, the infection by Myxidium parasites is emphasized as possible disease impeller, representing menace to the turtle conservation.