The morphological and molecular characterization of Henneguya rotunda n. sp., a parasite of the gill arch and fins of Salminus brasiliensis from the Mogi Guaçu River, Brazil

Abstract

A new species of myxosporea (Henneguya rotunda n. sp.) was found in the membrane of the gill arch and the fins of Salminus brasiliensis in the Mogi Guaçu River, municipality of Pirassununga, São Paulo state, Brazil. Morphological and morphometric analyses using light microscopy revealed parasites with similar characteristics at both infection sites. The mature spores found infecting the fins had oval spore body with 7.1 ± 0.2 μm in length, 5.6 ± 0.2 μm in width, 3.7 ± 0.1 μm in thickness, 16.4 ± 1.2 μm in length of the caudal process, and 23.6 ± 1.1 μm in total length of the spore. In a frontal view, the polar capsule was observed to be symmetrical with 3.4 ± 0.2 μm in length and 1.8 ± 0.1 μm in width. Mature spores contain six to seven turns of the polar filaments. The morphometric data concerning the spores obtained from plasmodia from the membrane of the gill arch were similar to those from the fins. Ultrastructure analysis revealed that the plasmodial wall was formed by a single membrane and had numerous pinocytotic canals connecting the outside of the plasmodia to the ectoplasm zone. Beyond that, various electron-translucent vesicles also were observed at the periphery of the plasmodium. The molecular analyses of the 18S rDNA gene from the spores obtained from the gill arch membrane and fin membrane showed that these sequences shared 100% similarity. Phylogenetic studies using maximum parsimony and maximum likelihood methods demonstrated the polyphyletic clustering of the myxosporean parasites of characiform fishes. H. rotunda n. sp. clustered as a sister species of Myxobolus pantanalis, also a parasite of S. brasiliensis.

Supplemental description and molecular characterization of Myxobolus miyarii Kudo, 1919 (Myxosporea: Myxobolidae) infecting intestine of Amur catfish (Silurus asotus)

“…The present phylogenetic analysis of the Myxobolus and Henneguya parasites of fish showed phylogenetic affinity of the fish hosts provided the strongest evolutionary signal, consistent with the previously reported (Fiala 2006;Carriero et al 2013;Moreira et al 2014). The clustering of most of selected species occurred mainly based on the order, followed by family of host and M. miyairii cluster within a Siluriformes-infecting HenneguyaMyxobolus clade with a robust support, but independently from Ictaluridae-infecting Henneguya clade.…”

Morphology, ultrastructure and phylogeny of Myxobolus curimatae n. sp. (Myxozoa: Myxosporea) a parasite of Prochilodus costatus (Teleostei: Prochilodontidae) from the São Francisco River, Brazil

“…Sporogenesis of M. curimatae n. sp. has many similarities with other previously described myxozoan species [4,[30][31][32][33] with numerous mitochondria, generative cells, and pansporoblasts in different developmental stages and immature spores viewed below the ectoplasm layer, and mature spores in the deeper layer of the plasmodia, characterizing asynchronic development. A connective tissue layer composed of a thin colagenic fibril layer and fibroblast surrounded the plasmodium, as also pointed by others authors [5,34,35].…”

“…For this study, sixteen adult specimens of P. costatus (with average size of 34 [32][33][34][35][36][37][38][39][40] cm) were collected from the São Francisco River, in the city of Pirapora, Minas Gerais state, Brazil (17°12′75″S, 44°50′95″ W) in December 2011. The methodology of the present study was approved by the ethics research committee of Federal University of São Paulo (CEP: 0128/12), and is in accordance with Brazilian law.…”

Myxobolus marajoensis sp. n. (Myxosporea: Myxobolidae), parasite of the freshwater catfish Rhamdia quelen from the Brazilian Amazon region

“…Fish parasitized by the myxozoan species tend to form groups based on the type of environment (freshwater or marine) and taxon (FIALA, 2006;FERGUSON et al, 2008;ADRIANO et al, 2012;CARRIERO et al, 2013;MOREIRA et al, 2014). The lowest p distance recorded between M. marajoensis sp.…”