Anisakis simplex (Rudolphi, 1809)

Nagasawa, K. & Moravec, F., 2002, Larval anisakid nematodes from four species of squid (Cephalopoda: Teuthoidea) from the central and western North Paci ® c Ocean, Journal of Natural History 36 (8), pp. 883-891 : 885-886

Anisakis simplex (Rudolphi, 1809)

(®gure 2)

Third-stage larva (W ve specimens). Body 21 820±27 320 long and 412±474 wide; cuticle with very ®ne transverse striations. Cephalic end rounded, with prominent ventral cuticular tooth; latter 8±10 long, ventrally bent, sharply pointed. Anlagen of lips weakly developed. Oesophagus almost cylindrical, muscular, light-coloured, 1730±2580 long. Nerve ring 305±392 from anterior extremity. Ventriculus long, 960±1480, width 209±287, its posterior end obliquely shaped in lateral view. Renette cell very long, darkly coloured, extending anteriorly along ventral side of intestine to level of posterior end of ventriculus; excretory canal narrow, colourless, opening in excretory pore situated below ventral cephalic tooth. Intestine straight. Rectum short, hyaline; three small round unicellular rectal glands present. Tail rounded, 100±157 long, ending in sharp cuticular spike 12±20 long.

Hosts. Onychoteuthis borealijaponica Okada, 1927 (Onychoteuthidae) and Gonatopsis borealis Sasaki, 1920 (Gonatidae) .

Site of infection. Encapsulated in stomach wall.

Localities. Central North Paci®c Ocean (42ss39¾N, 179ss30¾W and 43ss39¾N, 179ss30¾W, both 23 June 1993 Ð O. borealijaponica ; 44ss39¾N, 179ss30¾W, 24 June 1993 Ð G. borealis ) and western North Paci®c Ocean (41ss20¾N, 147ss00¾E, 12 May 1982 Ð O. borealijaponic a).

Voucher specimens deposited. National Science Museum, Tokyo (NSMT, as 2935 to 2937) and Institute of Parasitology, ASCR, C Ïeske BudeÏjovice (Cat. No. N-617).

Comments

Larvae of the present material are morphologically identical with those reported by Nagasawa and Moravec (1995) from the Japanese common squid, Todarodes japonicus Steenstrup , of the Sea of Japan, but their body size and measurements are generally somewhat smaller, which may be considered an intraspeci®c variability. In the western North Paci®c Ocean, A. simplex larvae were reported from three species of squid hosts, T. paci W cus, O. bartramii and O. borealijaponica ( Oshima, 1972; Bagrov, 1982; Kurochkin and Solov’eva, 1982), but there are no records of this parasite from squids in the central North Paci®c Ocean.

Adult A. simplex is a parasite mainly of cetaceans and pinnipeds in cold temperate and polar waters ( Davey, 1971; Kuramochi et al., 1996) and conspeci®c third-stage larvae occur largely in various ®sh species, but also crustaceans, cephalopods and some other invertebrates ( Nagasawa, 1990b). This species is known as the main agent of human anisakiosis.