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

ROSSIN, M. ALEJANDRA; INÉS S. INCORVAIA; TIMI JUAN TOMÁS

Viña del Mar

Congreso; VIII International Symposium of fish parasites.; 2011

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