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

Abstract

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.

A new Myxobolus (Cnidaria: Myxosporea) infecting the ornamental catfish Corydoras schwartzi from the Purus River in Brazil

“…display a broad diversity and are widely exploited as an important source in the international aquatic pet trade, there are few studies about myxosporean infections in these smaller catfishes (Mathews et al 2017). Among approximately thirty-two species of Myxobolus described as infecting wild and farmed fish from the Amazon River basin and its main tributaries (Eiras et al 2014;Abrunhosa et al 2017;Naldoni et al 2018;Capodifoglio et al 2019), only one species was reported to infect Corydoras spp., i.e., Myxobolus niger Mathews, Maia & Adriano, 2016 described from the gill arch of C. melini Lönnberg & Rendahl, 1930(Mathews et al 2016. Our study reports, for the first time, a myxosporean species infecting C. schwartzi from the Amazon region and is hence the second to report a Myxobolus infection in Corydoras fish from South America.…”

“…The new species was compared with the four species of Myxobolus previously described infecting the intestine of South American freshwater fish: M. cunhai Penido, 1927, a (Molnár 1993;Eiras et al 2014;Abrunhosa et al 2017). Noticeable morphometric differences were observed between these species and M. adrianoi sp.…”

“…In the last years, a large number of myxosporean species has been described infecting different organs and tissues of wild and farmed South American freshwater fish (Mathews et al 2015;Velasco et al 2016;Vidal et al 2017;Abrunhosa et al 2017;Capodifoglio et al 2019), with some species causing considerable pathological issues such as reduction of epithelial area of the gill, myocarditis of the heart, deformation, displacement, retraction and compression of capillaries of the gill lamellae, large skin nodules, thickening of the tunica externa of the swim bladder with granulomatous reaction, perivascular edema in the interlamellar area, and stretching of the corneal epithelium and urinary bladder (Barassa et al 2003;Adriano et al 2009;Naldoni et al 2009;Matos et al 2014).…”