A new species of Neoascarophis (Cystilicolidae), a parasite of Macrourus carinatus (Gunther) from Patagonian waters.

ROSSIN, M.A.; INCORVAIA, I.S.; TIMI, J.T.

Viña del Mar

Simposio; VIII International Symposium on Fish Parasites; 2011

Universidad de Antofagasta, Chile

Nematodes of the cystidicolid genus Neoascarophis Machida, 1976 are all parasites of macrourid fishes, comprising at present five species. Some other unidentified species have also been reported in several fish species from the North and South Atlantic Ocean, including one from Macrourus carinatus (Günther) (Macrouridae) in the Southwest Atlantic Ocean. During a parasitological survey carried out on samples of M. carinatus from Patagonian waters, nematodes referable to Neascarophis were found in ulcers in the gastric mucose of fish. These nematodes represented a new species which closely resembles N. macrouri by the posterior position of the vulva (being equatorial in other species) and the dilated posterior extremity in females. However the new species differs from N. macrouri by its larger size, a larger muscular esophagus, and by the absence of caudal alae in males. SEM study of cephalic structures also showed morphological differences between both species, especially in the morphology of the submedian labia and lateral pseudolabia. In view on these differences a new species is proposed.