Scanning electron microscopic observations on Goezia spinulosa (Diesing, 1839) (Nematoda: Anisakidae) from Arapaima gigas (Cuvier, 1817)

The examined specimens were collected from pirarucu (A. gigas) coming from the Araguaia River, and presented the following characters: about 13.8 mm and 16.0 mm in length by 0.69 and 0.73 in maxima width for the males and females, respectively; a well defined cephalic extremity, with three large, distinct and depressed lips, each lip showing internally two lobes with bifid extremities; dorsal lip with two double papillae and sub-ventral lips, each one presenting a double sub-ventral papilla, a single lateral papilla and one amphid; the dentigerous borders recorded by Baylis (loc. cit.) could not be observed; triangular oral opening; body covered with circular spiny files, which increase in size gradually in direction to the middle portion of the body, and next decrease, always gradually, in direction to the posterior extremity; the spines are unlike each other, even when placed in the same file.