Hysterothylacium sinense, Li, Liang, An, Ruiyong & Zhang, Luping, 2007

Li, Liang, An, Ruiyong & Zhang, Luping, 2007, A new species of Hysterothylacium (Nematoda: Anisakidae) from marine fishes from Yellow Sea, China, with a key to the species of the genus Hysterothylacium, Zootaxa 1614, pp. 43-52 : 44-45

Hysterothylacium sinense sp. nov.

( Figs. 1–2 )

Type host: Astroconger myriaster (Brevoort) .

Other hosts: Trichiurus haumela (Forsskål) , Saurida elongata Temminck and Schlegel , Coryphaena hippurus Linnaeus , Sillago sihama (Forsskål) and Argyrosomus argentatus (Houttuyn) .

Site of infection: Intestine.

Date of collection: 28 September 2006.

Type locality: Shidao Island (122° 26’ 42’’ E; 36° 52’ 57’’ N), Yellow Sea, Shandong Province, China.

Prevalence and intensity: 12.1% (4 infected / 33 examined), 2–16 (7.3) specimens in Astroconger myriaster ; 4.5% (1 infected / 22 examined), 5 specimens in Trichiurus haumela ; 3.4% (1 infected / 29 examined), 4 specimens in Saurida elongate ; 6.3% (1 infected / 16 examined), 8 specimens in Coryphaena hippurus ; 4.3% (1 infected / 23 examined), 3 specimens in Sillago sihama ; 1.7% (1 infected / 60 examined), 2 specimens in Argyrosomus argentatus .

Type specimens: Holotype male (HBNU-0706), allotype female (HBNU-0707), paratypes: 8 male (HBNU-0708) and 5 female (HBNU-0709).

Etymology: The species name refers to its geographic location ( China).

Description: Medium sized, whitish nematodes, cuticle with fine, transverse striations. Lateral alae present, very broad. Anterior end with 3 lips; dorsal lip slightly smaller than sub-ventrals, with deep postlabial grooves and prominent lateral flanges. Proximal part of each lip with four lobes. Dorsal lip with 2 lateral double papillae; sub-ventral lips each with one amphid, one single papilla and one double papilla. Interlabia well developed, triangular with base wider than length, about 1/2 length of lips. Oesophagus long, slightly broader posteriorly than anteriorly. Nerve ring encircling oesophagus between first and second sixths of its length. Ventriculus almost spherical, approximately as wide as oesophagus. Ventricular appendix narrow, usually somewhat shorter than intestinal caecum. Excretory pore slightly posterior to nerve ring. Rectum hyaline, tube-shaped, surrounded by 3 large, unicellular rectal glands. Tail conical, relatively short, tip of male tail without any ornamentation; tip of female tail covered with numerous nodular protuberance.

Male (based on 9 mature specimens): Body 23.1–40.1 (32.0) mm long, maximum width 197–345 (283). Dorsal lip 78.6–123 (102) long, 108–116 (110) wide. Sub-ventral lips 101–125 (113) long, 98–115 (111) wide. Interlabia 49–58 (50) long, 68–113 (91) wide. Lateral alae 49–87 (67) wide in the level of oesophagus. Oesophagus 2.04–3.45 (2.74) mm long, 7.2–10.3 (9.0) % of body length (BL), 69–123 (95) wide. Nerve ring 473–682 (593) from anterior extremity; excretory pore 491–742 (640) from anterior extremity. Ventriculus 97–152 (131) long by 87–151(122) wide. Ventricular appendix 1.07–2.43 (1.67) mm long by 49–114 (87) wide. Intestinal caecum 1.26–2.33 (1.78) mm long, 61–71 (65) % of oesophageal length; 58–113 (90) wide. Ratio of intestinal caecum to ventricular appendix 1:0.80–1.08 (1:0.94). Ejaculatory duct 1.21–2.28 (1.66) mm long, 4.1–7.1 (5.2) % of BL. Spicules slender, of equal length, 1.65–2.67 (2.10) mm long, 102–166 (127) % of ejaculatory duct (ED) and 5.1–9.5 (6.7) % of BL. Gubernaculum absent. Tail 78–124 (95) long; tail tip 19–29 (21) long, without ornamentation. Caudal papillae arranged as follows: 22–27 pairs of preanal papillaee, 1 pair of very small paranal papillae and 3 pairs of postanal papillae.

Female (based on 6 gravid specimens): Body 29.3–43.9 (38.4) mm long, maximum width 293–362 (324). Dorsal lip 87–154 (123) long, 94–133 (124) wide. Sub-ventral lips 102–145 (136) long, 98–131 (118) wide. Interlabia 49–50 (49) long, 87–113 (92) wide. Lateral alae 49–78 (66) wide. Oesophagus 2.74–3.40 (3.03) mm long, 6.8–9.9 (8.1) % of BL; maximum width 97–134 (121). Nerve ring 531–633 (604) from anterior extremity; excretory pore 580–752 (672) from anterior extremity. Ventriculus 121–153 (144) long by 97– 154 (130) wide. Ventricular appendix 1.51–1.89 (1.69) mm long by 68–97 (80) wide. Intestinal caecum 1.99– 2.28 (2.11) mm long, 65.1–75.0 (69.7) % of oesophageal length; 97–122 (113) wide. Ratio of intestinal caecum to ventricular appendix 1:0.68–0.95 (1:0.81). Tail length 232–321 (262), tail tip 19–20 (19) long, with numerous nodular protuberances. Vulva slit-like, without salient lips, located pre-equatorially, 23.9–31.7 (28.7) % from anterior end. Vagina muscular, directed posteriorly. Uteri opposed. Eggs embryonated, oval, 36.0–38.1 (37.5) long by 37.3–41.1 (39.1) wide.

Figures

FIGURE 1. Hysterothylacium sinense sp. nov. A, cephalic end of male, dorsal view; B, cephalic end of male, ventral view; C, vulval region; D, egg; E, anterior part of body of male, ventral view; F, posterior region of male, lateral view; G, caudal region of male, lateral view; H, tip of male tail; I, tail region of female, lateral view; J, tip of female tail; Scale bars in mm.

FIGURE 2. Hysterothylacium sinense sp. nov. A, cephalic extremity, lateral view; B, cephalic extremity, apical view; C, dorsal lip; D, sub-ventral lip; E, anterior end of male, lateral view; F, posterior region of male; G, tip of male tail; H, posterior region of female, lateral view; I, tip of female tail; J, paranal region of male; K, preanal papillae; i, interlabium; d, double papillae; s, single papillae; am, amphid; pp, paracloacal papillae; sp, spicules.