Philometroides huronensis Uhazy, 1976

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 51-52

Philometroides huronensis Uhazy, 1976

Description (after Uhazy 1976). With characteristics of the genus. Body cylindrical with bluntly narrowing extremities. Cuticle longitudinally striated with numerous irregularly distributed bosses. Mouth opening surrounded by three lips. Cephalic papillae comprise six inner and four pairs outer papillae. Amphids distinct. Oesophagus inflated anteriorly with a short anterior muscular portion and longer posterior glandular portion. Dorsal oesophageal gland prominent. Nerve ring at posterior end of muscular oesophagus ( Fig. 34 A).

Mature males: 2.8–3.6 long, and 0.041–0.05 wide. Muscular oesophagus 0.159–0.245 and glandular oesophagus 0.214–0.398 long. Dorsal oesophageal gland large with distinct nucleus ( Fig. 34 A). Nerve ring 0.128– 0.191, hemizonid 0.150–0.309, excretory pore 0.167–0.301, right anterior deirid 0.180–0.355, and left anterior deirid 0.197–0.356 from anterior end. Right posterior deirid 0.139–0.272, and left posterior deirid 0.310–0.513 from posterior end. Intestine ligament-like throughout its length. Monorchic testis at level of oesophago-intestinal junction. Vas deferens and ejaculatory duct packed with spermatozoa. Spicules slender, unequal: right one 0.122– 0.140, left one 0.110–0.134, and gubernaculum 0.070–0.082 long. Anus subterminal. Caudal extremity distinctly lobed, with one pair pre-cloacal and two pairs post-cloacal papillae ( Fig. 34 B). Phasmids terminal. Cuticle longitudinally striated and covered with minute bosses.

Gravid females: 35.4–101.0 long, and 0.600–0.850 wide. Muscular oesophagus 0.29–0.48 and glandular oesophagus 1.0–1.9 long. Dorsal oesophageal gland large with distinct nucleus ( Fig. 34 C). Nerve ring 0.270–0.440 from anterior end. Uterus 34.0–98.8 long. Intestine ligamentous posteriorly; anus not patent. Caudal papillae absent. Prominent hypodermis giving rise to caudal, ventro-lateral extensions ( Fig. 34 D). Cuticular bosses distributed generally on body but clustered in regions of caudal hypodermal extensions ( Fig. 34 D). Amphidelphic, didelphic, uterus thin walled and packed with 1st -stage larvae 0.362–0.406 long. 97% of body length occupied by uterus ( Fig. 34 C,D). Ovaries often reflexed and close to anterior and posterior ends of body. Vulva and vagina absent ( Fig. 34 C,D).

Comments: Uhazy (1976) also provided measurements of subgravid and mature females.

Sites: fins, mesenteries, swim bladder, subcutaneous

Hosts: Catostomus catostomus (4, 5, 7, 10); Catostomus commersonii (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12);

Catostomus macrocheilus (7, 10); Moxostoma macrolepidotum (4, 5)

Distribution: British Columbia, Manitoba, Ontario, Quebec

Records: 1. Uhazy 1976 (ON); 2. Uhazy & Anderson 1976 (ON); 3. Uhazy 1977a (ON); 4. Uhazy 1977b (ON); 5.

Uhazy 1977c (ON); 6. Uhazy 1978 (ON); 7. Anon. 1978 (BC); 8. Chan 1980 (ON); 9. Molnar et al. 1982

(ON); 10. Arai & Mudry 1983 (BC); 11. Mackie et al. 1983 (ON); 12. Dubois et al. 1996 (QC)

Figures

FIGURE 34. Philometroides huronensis Uhazy, 1976. A. male, anterior region, ventro-lateral view; B. male, posterior region, lateral view; C. gravid female, anterior region, lateral view; D. gravid female, posterior region, ventral view. (Redrawn from Uhazy 1976)