Morphology and small subunit rDNA-based phylogeny of a new Henneguya species, infecting the ornamental fish Corydoras leucomelas from the Peruvian Amazon

- A new species of Henneguya (Myxosporea) is described.
- Morphological and molecular data of the new species are provided.
- This is the first Henneguya species reported in a fish from Peruvian Amazon.

A new species of Myxosporea, Henneguya loreotoensis n. sp. is described parasitizing the gill filaments from 17 of 35 specimens (48.5%) of Corydoras leucomelas (Siluriformes: Callichthyidae) caught in the Nanay River, near village Ninarumi, in the Loreto state, Peru. Mature spores were ellipsoidal in shape from the frontal view, measuring 36.2 ± 0.1 μm (36.1-36.3) in total length, 14.3 ± 0.1 μm (14.2-14.4) in body length, 5.1 ± 0.1 μm (4.9-5.3) in width and 21.9 ± 0.1 μm (21.8-22.0) in the caudal process. The two polar capsules were symmetrical and elongated, measuring 5.1 ± 0.1 μm (4.9-5.3) in length and 2.4 ± 0.2 μm (2.1-2.7) in width, containing a polar filament with five coils arranged obliquely to the longitudinal axis. The sporoplasm was binucleate. Partial sequencing of the ssu-rDNA of H. loretoensis n. sp. resulted in a total of 1676 nucleotides, and this sequence did not match any of the myxozoan available in the GenBank. The phylogenetic analysis shows H. loretoensis n. sp. as a sister species of Henneguya paraensis, another amazonian myxozoan parasite of Cichla temensis (Perciformes: Cichlidae).

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