Hysterothylacium marinum, (Linnaeus, 1767)

Moravec, F. & Nagasawa, Kazuya, 2000, Some anisakid nematodes from marine ® shes of Japan and the North Paci ® c Ocean, Journal of Natural History 34 (8), pp. 1555-1574 : 1566

Hysterothylaciu m marinum (Linnaeus, 1767)

( Figure 5 )

Ascaris marina Linnaeus, 1767 ; A. rigida Rudolphi, 1809 ; Contracaecum lophii Schuurmans- Stekhoven, 1935.

Description

Light-coloured nematodes of medium size with almost smooth cuticle. Cervical alae present, but very narrow. Lips approximately equal in size, provided with wide membranous ¯anges, these being broadest at middle of lips. Dorsal lip bearing two subdorsal double papillae; each subventral lip with one double subventral papilla and small simple papilla and amphid situated laterally; pulp of lips provided at either side with small rounded lobe at its anterior margin. Interlabia broad. Oesophagus narrow, long; ventriculus globular, ventricular appendix long, very narrow; intestinal caecum very long, distinctly longer than ventricular appendix, representing 46±69% of oesophagus length. Nerve ring encircling oesophagus approximately at border of ®rst and second ®fths of its length; excretory pore just below level of nerve ring. Tail of both sexes conical, ending in small process covered by ®ne rudimentary spines.

Male (three specimens). Length of body 22,351 ±27,666, maximum width 412±536. Lips 104±120 long, length of interlabia 28±48. Length of oesophagus 2575±2862. Nerve ring and excretory pore 600±653 and 679±713, respectively, from anterior extremity. Size of ventriculus 104±113 Ö 87; ventricular appendix indistinct. Intestinal caecum 1305±1696 long, representing 46±66% of oesophagus length. Spicules alate, 1496±1531 long, representing 5±7% of body length. Total of 34±41 pairs of subventral papillae present, 26±33 being preanals, two adanals and six postanals; pair of papilla-like phasmids present. Tail 76±84 long, length of caudal process 6±10.

Female (two young specimens). Body 26,224 ±30,591 long, maximum width 556. Lips 100±112 long, length of interlabia 44±48. Length of oesophagus 2801±3219. Nerve ring and excretory pore 566±592 and 618±626, respectively, from anterior extremity. Size of ventriculus 60±88 Ö 60±80; length of ventricular appendix and intestinal caecum in smaller specimen 1560 and 1984 (69% of body length), respectively. Length ratio of ventricular appendix and caecum 1: 1.6. Vulva situated in anterior half of body, 9270 ±10,815 from anterior extremity (at 35% of body length); vagina directed posteriorly from vulva. No eggs present in uteri. Tail 244±400 long, length of caudal process 6±12. Rectum a hyaline tube surrounded by three large unicellular rectal glands.

Figures

FIG. 5. Hysterothylacium marinum (Linnaeus, 1767) from L. litulon: (A) anterior end of female; (B,C) cephalic end of female and male, dorsal and ventral views; (D) tail tip of male; (E) tail tip of female; (F) tail of male; (G) posterior end of male; (H) tail of female. Scale bars in mm.