Myxobolus saladensis sp. nov., a new species of gill parasite of Mugil liza (Osteichthyes, Mugilidae) from Samborombón Bay, Buenos Aires, Argentina

Myxosporean Myxobolus saladensis sp. nov. in the gills of Mugil liza Valenciennes, 1836 from Samborombón Bay was described by light and electron microscopy studies. Spores were pyriform and binucleated, measuring 10.63±0.36 µm (n=20) long, 9.24±0.50 µm (n=20) wide and 4.13±0.36 µm (n=20) thick, included in polysporic cyst-like plasmodia. Elongated pyriform polar capsules were of equal size (3.84±0.27 µm long and 2.30±0.12 µm wide). The sporoplasm contained some sporoplasmosomes. Each PC contained a polar filament with 4-5 coils obliquely arranged in relation to the polar capsules axis. The PC wall was composed of two layers of different electron densities. Based on the morphological and ultrastructure differences of the spore to those of previously described species of Myxobolus, we describe a new species, Myxobolus saladensis sp. nov.(AU)

Myxobolus marajoensis sp. n. (Myxosporea: Myxobolidae), parasite of the freshwater catfish Rhamdia quelen from the Brazilian Amazon region / Myxobolus marajoensis sp. n. (Myxosporea: Myxobolidae), parasita do bagre de água doce Rhamdia quelen da região da Amazônia brasileira

This study provides morphological and molecular data of a new parasite species found in the muscle layer of the intestinal tract of the South American silver catfish, Rhamdia quelen from Marajó Island region (Pará State, Brazil), an important fishery resource with recognized potential for fish farming. The morphology of these parasites was reanalyzed and phylogenetic analyses were run on their 18S rDNA gene sequences. The spores were morphologically distinct from those of other Myxobolus species described previously. The obtained partial sequence of the 18S rDNA gene sequences of the new species were compared to those of 24 other Myxobolus and Henneguya species available in GenBank. The results of morphological and molecular analyses indicated clearly the existence of a new species, Myxobolus marajoensis sp. n.(AU)

Este estudo fornece dados morfológicos e moleculares de um novo parasita encontrado na parede intestinal do jandiá, Rhamdia quelen coletado na região da ilha do Marajó (Estado do Pará, Brasil), um importante recurso pesqueiro com potencial para aquicultura. Foram realizadas comparações morfológicas deste parasita e análises filogenéticas da região do gene 18S rDNA sequenciada. Os esporos foram morfologicamente distintos das espécies de outros Myxobolus descritos anteriormente. A sequência parcial obtida do gene 18S rDNA da nova espécie foi comparada com outras 24 espécies de Myxobolus e Henneguya retiradas do GenBank. Os resultados de análises morfológica e molecular indicaram claramente a existência de uma nova espécie, Myxobolus marajoensis sp. n.(AU)

Myxobolus saladensis sp. nov., a new species of gill parasite of Mugil liza (Osteichthyes, Mugilidae) from Samborombón Bay, Buenos Aires, Argentina

Myxosporean Myxobolus saladensis sp. nov. in the gills of Mugil liza Valenciennes, 1836 from Samborombón Bay was described by light and electron microscopy studies. Spores were pyriform and binucleated, measuring 10.63±0.36 µm (n=20) long, 9.24±0.50 µm (n=20) wide and 4.13±0.36 µm (n=20) thick, included in polysporic cyst-like plasmodia. Elongated pyriform polar capsules were of equal size (3.84±0.27 µm long and 2.30±0.12 µm wide). The sporoplasm contained some sporoplasmosomes. Each PC contained a polar filament with 4-5 coils obliquely arranged in relation to the polar capsules axis. The PC wall was composed of two layers of different electron densities. Based on the morphological and ultrastructure differences of the spore to those of previously described species of Myxobolus, we describe a new species, Myxobolus saladensis sp. nov.

Myxozoan infection in the muscle layer of the intestine of Rhamdia quelen from the Amazon River Basin, Brazil / Infecção por Myxozoa na camada muscular intestinal do Rhamdia quelen da Bacia do Rio Amazonas, Brasil

The present study investigated the morphology and pathology associated with the occurrence of cysts caused by Myxobolus sp. in the intestine of the silver catfish Rhamdia quelen . Comparisons with the other Myxobolus species that infect the intestines of cyprinids and siluriforms revealed that the pyriform spores of Myxobolus sp. are similar in shape to those described previously in M. miyairii, M. duodenalis and M. cunhai, but different in size. Morphometric analyses revealed that mature spores of Myxobolus sp. (10.9 x 5.1m) are smaller than those of most species except M. cunhai (10.0 x 5.0m), which has been described infecting the Brazilian catfish Pimelodus clarias , although the spores differ morphologically in relation to the shape of the polar capsules. Further research is necessary in order to clarify the taxonomic and phylogenetic relationships among these congeneric species.(AU)

O presente estudo investigou a morfologia e patologia associada com a ocorrência de cistos de Myxobolus sp. no intestino do peixe siluriforme Rhamdia quelen . Comparações com outras espécies de Myxobolus que têm infectado intestinos de carpas e bagres de água doce demonstraram que os esporos piriformes de Myxobolus sp. são similares no formato dos anteriormente descritos para M. miyairii, M. duodenalis e M. cunhai , diferindo, no entanto, quanto ao tamanho. As análises morfométricas revelaram que os esporos maduros de Myxobolus sp. (10,9 x 5,1m) são menores do que os da maioria das espécies, exceto para M. cunhai (10,0 x 5,0m), que foi descrito infectando o bagre brasileiro Clarias pimelodus , embora os esporos sejam diferentes morfologicamente em relação à forma das cápsulas polares. Futuras pesquisas são necessárias para esclarecer as relações taxonômicas e filogenéticas entre espécies congêneres.(AU)