Species of Ascarophis van Beneden, 1870 (Nematoda: Cystidicolidae) in North Atlantic fishes

Abstract

Ascarophis arctica Poljansky, 1952, A. filiformis Poljansky, 1952 and Ascarophis extalicola sp.nov. are described from cod, Gadus morhua L. (Gadidae), collected in the northwestern Atlantic. All three species have narrow pseudolabia, four sublabia, deirids anterior to the nerve ring, and six postanal papillae. Ascarophis extalicola sp.nov. has a small blunt elevation on each pseudolabium, body length of 4 to 6 mm in males and 6 to 9 mm in females, vulva well posterior to midbody, right spicule 61 to 83 μm long, left spicule 276 to 359 μm long, and eggs with many filaments at one pole. This species occurs in the rectum and posterior intestine of cod and Myoxocephalus octodecemspinosus. Ascarophis arctica has pseudolabia each with a prominent conical apex, pronounced cuticular striations, left spicule 585 to 882 μm long with a bent and blunt tip, and eggs with many filaments at both poles. Ascarophis arctica infects the stomach of cod and eight other fish species. Ascarophis filiformis has pseudolabia each with a prominent conical apex, faint cuticular striations, left spicule 271 to 392 μm long with a straight and pointed tip, and eggs with two filaments at one pole. Ascarophis filiformis was found only in the stomach of cod. Local distributions, prevalence, and intensity of each species in cod are noted.