![]() ![]() Of the five mentioned freshwater species, only C. In fact, only five species have been reported from freshwater teleosts worldwide: Ceratomyxa anguillae from the gall bladder of Anguilla anguilla from France, Ceratomyxa hilsae from the gall bladder of Hilsa ilisha from India, Ceratomyxa hongtzensis from the gall bladder of Pelteobagrus eupogon from China, Ceratomyxa hungarica from the gall bladder of Proterorhinus marmoratus from Hungary and Ceratomyxa shasta from the digestive tract of Oncorhynchus mykiss from the United States of America (Chakravarty 1939, Noble 1950, Tuzet & Ormières 1957, Hsieh & Chen 1984, Molnár 1992). These are all species infecting the gall bladder of marine fish hosts. Spores contain two subspherical capsules and a binucleate sporoplasm or, more rarely, two uninucleate sporoplasms (Lom & Dyková 1992).ĭespite having a worldwide distribution, only three species of Ceratomyxa have been described from South American fish hosts: Ceratomyxa dissostichi from Dissostichus eleginoides from the Falklands islands, Ceratomyxa curvatafrom Odontaspis americanus and Ceratomyxa hippocampi from Hippocampus punctulatus, both from the Brazilian Atlantic coast (Cunha & Fonseca 1918, Brickle et al. Ceratomyxaspp have elongated, crescent-shaped or arcuate spores with shell valves that are frequently conical, exceeding in length the axial diameter of the spore. The genus CeratomyxaThélohan, 1892, constitutes one of the largest genera within the class Myxosporea of the phylum Myxozoa, comprising about 190 species, the great majority of which are coelozoic parasites infecting the gall bladder of marine teleosts (Eiras 2006, Lom & Dyková 2006). ![]() therefore representing the first description of a freshwater ceratomyxid from the South American region. Considering the morphometric data analyzed from the microscopic observations, as well as the host species and its geographical location, this paper describes a new myxosporean species, herein named Ceratomyxa microlepis sp. Two equal-sized subspherical polar capsules measuring 2.2 ± 0.3 µm in diameter were located at the same level, each possessing a polar filament with 5-6 coils. ![]() The lateral projections were asymmetric, one measuring 18.1 ± 0.5 µm (n = 25) in thickness and the other measuring 17.5 ± 0.5 µm (n = 25) in thickness. The spores body measured 5.2 ± 0.4 µm (n = 25) in length and 35.5 ± 0.9 µm (n = 25) in total thickness. ![]() Light and transmission electron microscopy revealed elongated crescent-shaped spores constituted by two asymmetrical shell valves united along a straight sutural line, each possessing a lateral projection. A new ceratomyxid parasite was examined for taxonomic identification, upon being found infecting the gall bladder of Hemiodus microlepis (Teleostei: Hemiodontidae), a freshwater teleost collected from the Amazon River, Brazil. ![]()
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