Lappetascaris sp.

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 : 887-889

Lappetascaris sp. Type A

(®gure 3)

Third-stage larva (16 specimens). Body whitish, elongate, 15 250±32 590 long and 265±647 wide. Cuticle almost smooth. Whole body with conspicuous, large, light-coloured hypodermal cells. Cephalic end narrowed, truncated, with weakly developed anlagen of lips anteriorly provided with transparent cuticular mounds surrounding mouth opening. Ventral part of cephalic end protruding more anteriorly than dorsal one. Anlagen of lips bearing at their outer sides sclerotized supports exceeding base of lip anlagen posteriorly; posterior parts of these formations appearing, in both lateral and dorsoventral views, as small posterior processes 36±98 long. Oesophagus almost cylindrical, without any anterior inātion, measuring 1090±2910; anterior half of oesophagus with conspicuous dorsal oesophageal gland, 720±1620 long and 49±98 wide. Nerve ring and excretory pore 294±470 and 382±566, respectively, from anterior extremity. Ventriculus elongate-oval, measuring 206± 5773 98 ±309. Posterior ventricular appendix very long, measuring 10 350±24 270 (64±86% of body length). Intestine straight, light-coloured. Intestinal caecum dorsal, extending anteriorly almost to level of excretory pore, 1280 ±2760 long. Length ratio of intestinal caecum and ventricular appendix 1:6.6 ±12.4. Rectum hyaline tube. Three oval unicellular rectal glands well developed. Tail conical, 140±294 long, with small cuticular spike (6±8) at tip.

Hosts. Thysanoteuthis rhombus Troschel, 1857 (Thysanoteuthidae) , Ommastrephes bartramii (LeSueur, 1821) (Ommastrephidae) , Onychoteuthis borealijaponica Okada, 1927 (Onychoteuthidae) and Gonatopsis borealis Sasaki, 1920 (Gonatidae) .

Site of infection. Musculature of mantle.

Localities. Central North Paci®c Ocean (25ss29¾N, 164ss55¾W, 25 May 1992 Ð O. bartramii ; 39ss39¾N, 179ss30¾W, 19 June 1993 Ð O. borealijaponic a; 41ss39¾N, 179ss30¾W, 22 June 1993 Ð O. borealijaponica ; 42ss39¾N, 179ss30¾W, 23 June 1993 Ð O. borealijaponica ; 44ss39¾N, 179ss30¾W, 25 June 1993 Ð G. borealis ; 25ss29¾N, 164ss55¾W, 25 May 1992) and western North Paci®c Ocean (27ssN, 142ssE [near Ogasawara Islands], 14 June 1996 Ð T. rhombus ; 42ss30¾N, 145ss00¾E, 23 July 1982 Ð O. borealijaponica ).

Voucher specimens deposited. National Science Museum, Tokyo ( NSMT, as 2938 to 2941) and Institute of Parasitology, ASCR, C Ïeske BudeÏjovice (Cat. No. N-618).

Comments

Larvae of this type designated as Lappetascaris sp. larvae have already been reported by Nagasawa and Moravec (1995) from the mantle musculature of the Japanese common squid, Todarodes paci W cus, from the Sea of Japan. They discussed in detail their systematic status and indicated that many previous records of anisakid larvae from the mantle of squids in the western North Paci®c Ocean reported by various authors as Contracaecum , Thynnascaris or Hysterothylacium were, in fact, identical with Lappetascaris sp. Larvae of this type also occur in Todarode s sagittatus angolensis Adam oOE the southern coast of Australia, in Ommastrephes bartramii from the waters of eastern Philippines as well as in the mantle of Atlantic squid ( Sheenko, 1991). Although Bower and Margolis (1991) did not mention the morphology of anisakid larvae from O. bartramii in the eastern North Paci®c Ocean (oOE the west coast of Canada), designated as Hysterothylacium sp. , the large-sized larvae (20±35 mm long) collected by them from the mantle wall of squids were undoubtedly identical with those of Lappetascaris sp. Type A of the present material. According to Sheenko (1991), at least part of the nematodes described from squids as Porrocaecum sp. 1 by Gaevskaya (1977), Gaevskaya and Nigmatullin (1981), Gaevskaya et al. (1983, 1986) and Naidenova et al. (1985), as well as those reported as Contracaecum sp. 1 Type II A of Brunsdon in Boyle (1966) from New Zealand, should be considered identical with the above-mentioned larvae. This indicates a wide geographical distribution of Lappetascaris sp. Type A larvae in oceanic squid populations.

The morphology of larvae of the present materal is identical with that described by Nagasawa and Moravec (1995), but the range of their measurements is considerably greater. Nagasawa and Moravec (1995) presuppose that these larvae from the mantle of squids belong to a hitherto undescribed species of Lappetascaris , the de®nitive host of which is an, as yet unknown, predatory marine ®sh.