Life cycle of Acanthostomoides apophalliformis (Trematoda, Cryptogonimidae) from Percichthys trucha (Pisces, Percichthydae) in Patagonia, Argentina.

OSTROWSKI DE NÚÑEZ, M.; SEMENAS, L.; VIOZZI, G.; FLORES, V. AND BRUGNI, N.

Olsztyn Polonia

Congreso; XVlll Congress of the Polish Parasitological Society and the Jubileum, 50th Anniversary of PPS Foundation.; 1998

Sociedad de Parasitología de Polonia.

Acanthostomoides apophalliformis Szidat, 1956 was first described upon few specimens from two Percichthys trucha (Cuvier & Valenciennes) Girard, captured at the River Limay in Patagonia. Recent results show that it is a common parasite of the intestine and pyloric caeca of P. trucha, present high prevalence and intensity in several water bodies of Argentina between Lake Quillén (39º25’S, 71º20’W Neuquén Province) and Lake Rivadavia (42º40’S, 71º41’W Chubut Province). It is also present in lakes of Chile. Occasionally, it was also found in the stomach of Oncorhynchus mykiss (Walbaum, 1792). The metacercaria was found in the liver, mesenterie, gills,etc of Galaxias maculatus (Jenyns, 1842) and G. platei Steindachner, 1898. The mature metacercaria has fairly well developed gentalia and double crown of spines identical to that of adults. The cercaria was found in the prosobranch snail, Heleobia hatcheri (Pilsbry, 1911). Two morphological types were identified, one with a transparent tail with orange pigment in the proximal tenth and moiré than 50 acicular spines at the oral sucker and another with an opaque tail with a transparent distal end and 30-40 acicular spines. Both types were exposed to G. maculatus, captured in a lake where the definitive host are not present. Identical metacercaria were obtained, which were indistinguishable from those naturally found in G. maculatus. Although experimental infestation to obtain the adult has been unsuccessful up to now, there is no doubt that the experimentally obtained metacercariae correspond to A. apophalliformis, because no other of Cryptogonimidae with this characteristic double crown of spines is known in the area. At present, it cannot be established whether A. apophalliformis, represents only one species with two different morphotypes of cercariae or a group of sibling species. The species is redescribed and its distribution on Patagonian lakes shown.