Mullets (Mugilidae) are economically-important fish exploited extensively by artisanal fisheries on the Amazon coast of Brazil. In the present study, 150 specimens of redeye mullet (Mugil rubrioculus) acquired from the public fish market were examined, and the gill filaments of 90 (60%) were found to be infected with spores of Myxobolus. The mature spores were spherical, with a mean diameter of 6.28±0.33 μm, and had polar capsules of equal size (2.47±0.34 μm in length and 1.58±0.27 μm in width). The 18S rRNA sequence of the parasite was compared with those of other myxosporidian species available in the GenBank database. The morphological and molecular characteristics of the parasite indicate strongly the existence of a new species, denominated Myxobolus bragantinus n. sp., the first case of a new myxosporidian species to be found in this host. [Zoobank: urn:lsid:zoobank.org:act:E00F72E1-9302-423F-BA4E-51C05D0770C8]

No abstract

Kudoa ajurutellus n. sp. (Multivalvulida: Kudoidae) is described as a parasite of the Bressou catfish, Aspistor quadriscutis (Siluriformes) collected at Ajuruteua beach, northeastern Pará, Brazil. The new species is described based on the morphology of the spores and the sequence of the 18S rDNA. This parasite was found only in the skeletal muscular tissue of fish hosts. In the apical view, the spores were pseudo-quadrangular in shape, with rounded borders, and four symmetrical capsules. The spores are 6.63±0.53 μm in length and 8.16±0.75 μm in width. The polar capsules are piriform, 3.45±0.30 μm in length and 1.87±0.15 μm in width. The phylogenetic analysis based on the sequence of the 18S rDNA gene indicated that the new species is clearly distinct from all other Kudoa species, and that the degree of differentiation is constant with the existence of a new species of the genus Kudoa. This is the first marine Kudoa species recorded in northeastern of the State of Pará.