Four species of digeneans, including Allocreadium patagonicum sp n. (Allocreadiidae), from freshwater fishes of Patagonia, Argentina

Four species of adult digeneans are reported from freshwater fishes of two lakes in Neuquen, Patagonia, Argentina. Allocreadium patagonicum sp. n. (Al locreadiidae) is described from the intestine of Percichthys colhuapiensis MacDonagh and Percichthys trucha (Cuvier et Valenciennes) (Percichthyidae) from Lago Alumine. Three species redescribed are: Acanthostomoides apophall iformis Szidat, 1956 (Acanthostomidae) from the intestine of P. colhuapiens is and P. trucha from Lago Alumine and of Salmo trutta (Linnaeus) (Salmonid ae) from Lago Huechulafquen; Deropegus patagonicus (Szidat, 1956) comb. n. (= Genarches patagonicus Szidat, 1956) (Derogenidae) from the stomach of P. colhuapiensis, P. trucha, Oncorhynchus mykiss (Walbaum) (Salmonidae) and S alvelinus fontinalis (Mitchill) (Salmonidae) from Lago Alumine and of S. tr utta from Lago Huechulafquen; and Austrocreadium papilliferum Szidat, 1956 from the intestine of P. trucha from Lago Alumine. The genus Polylekithum A rnold, 1934 is considered a synonym of the genus Allocreadium Looss, 1900. The genus Austrocreadium Szidat, 1956 is removed to the family Homalometrid ae.