Raphidascaris acus (Bloch, 1779) Railliet & Henry, 1915

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 146-148

Raphidascaris acus (Bloch, 1779) Railliet & Henry, 1915

Synonyms: Raphidascaris canadensis Smedley 1933 ; Raphidascaris laurentianus Richardson, 1937 ; Raphidascaris alius Lyster, 1940

Description (after J. D. Smith 1984a). With characteristics of the genus.

Males: 31.5–39.5 (mean 35.3) long, 0.063–0.83 (0.69) maximum width. Lips 0.092–0.118 (0.102) long. Small triangular elevation present between bases of subventral lips ( Fig. 84 A). Nerve ring 0.63–0.83 (0.69) and excretory pore 0.73–0.88 (0.80) from anterior end. Preventriculus 3.45–4.11 (3.73) long. Ventriculus and ventricular appendix 1.44–2.07 (1.80) long ( Fig. 84 B). Testis tightly coiled, anterior end 6.05–7.84 (6.91) from anterior end of worm. Vas efferens short. Seminal vesicle broad and thin-walled. Ejaculatory duct 1.70–2.57 (2.19) long. Left spicule 0.586–0.802 (0.686) and right spicule 0.544–0.773 (0.681) long. Gubernaculum absent. Caudal papillae extending 3.10–4.27 (3.70) anterior to anus: 16–21 (18) pre-cloacal pairs, two pairs or one pair doubled ad-cloacal, and four pairs post-cloacal. Tail conical, 0.235–0.291 (0.250) long ( Fig. 84 C). Phasmids lateral, 0.067–0.140 (100) from tip of tail.

Females: 40.5–49.2 (44.5) long, 0.81–1.07 (0.93) maximum width. Lips 0.93–0.132 (0.117) long. Nerve ring 0.60–0.74 (0.68) and excretory pore 0.75–0.84 (0.78) from anterior end. Preventriculus 3.51–4.62 (4.18) long.

Ventriculus and ventricular appendix 1.37–2.23 (1.83) long. Vulva 9.83–11.65 (10.85) from anterior end. Didelphic, opisthodelphic, with many eggs, 0.092–0.111 (0.101) x 0.083–0.101 (0.092). Oviducts ascending and descending, not extending anterior to vulva. Ovaries long, much folded, mainly posterior to uterus. Tail conical, 0.50–0.73 (0.61) long. Phasmids 0.18–0.26 (0.22) from tip of tail.

Site: intestinal lumen

Hosts: Catostomus catostomus (25); Catostomus commersonii (24, 44); Chrosomus eos (44); Coregonus artedi (24); Coregonus clupeaformis (15, 23, 24, 25, 36); Esox lucius (1, 4, 5, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 28, 30, 31, 32, 35, 37, 38, 39, 40, 43); Esox masquinongy (6, 22, 34); Hiodon alosoides (39, 43); Lota lota (25, 33, 45); Micropterus dolomieu (25); Oncorhynchus gorbuscha (29); Oncorhynchus mykiss (26); Perca flavescens (12, 23, 24, 27, 28, 32, 39, 42, 43); Salvelinus fontinalis (2, 3, 25, 26, 41, 44); Sander vitreus (24, 25, 27, 30, 39, 43, 45)

Distribution: Alberta, Labrador, Manitoba, Northwest Territories, Ontario, Quebec, Saskatchewan, Yukon Territory

Records: 1. Smedley 1933 (MB, SK); 2. Richardson 1937 (QC); 3. Lyster 1940 (QC); 4. Miller 1945 (AB); 5. Rawson 1951 (NT); 6. Choquette 1951c (QC); 7. Stewart-Hay 1951a (MB); 8. Stewart-Hay 1951b (MB); 9. Stewart-Hay 1952a (MB); 10. Stewart-Hay 1952b (MB); 11. Stewart-Hay 1953a (MB); 12. Dickson 1964 (MB); 13. Chinniah & Threlfall 1978 (LB); 14. Gordon et al. 1978 (QC); 15. Pybus & Samuel 1978 (AB); 16. Thompson & Threlfall 1978 (QC); 17. Kinnis & Curtis 1981 (QC); 18. Leong & Holmes 1981 (AB); 19. Samuel 1981 (AB); 20. J. D. Smith & Anderson 1981 (ON); 21. J. D. Smith & Anderson 1982 (ON); 22. Anthony 1983 (ON); 23. McAllister & Mudry 1983 (AB); 24. Poole 1983 (MB); 25. J. D. Smith 1984a (ON); 26. J. D. Smith 1984b (ON); 27 . Poole & Dick 1985 (MB); 28. Samuel 1985 (AB); 29. Anthony 1986 (ON); 30 . Poole & Dick 1986 (MB); 31. Shostak & Dick 1986 (MB); 32. J. D. Smith 1986 (ON); 33. Anthony 1987 (ON); 34. Dechtiar & Christie 1988 (ON); 35. Dechtiar et al. 1988 (ON); 36. Stock 1988 (AB); 37. Szalai & Dick 1988 (MB); 38. Shostak & Dick 1989 (MB); 39. Szalai 1989 (MB); 40. Szalai & Dick 1989 (MB); 41. Marcogliese & Cone 1991a (LB, QC); 42. Szalai & Dick 1991 (MB); 43. Szalai et al. 1992a (MB); 44. Dubois et al. 1996 (QC); 45. Baldwin & Goater 2003 (AB)

Figures

FIGURE 84. Raphidascaris acus (Bloch, 1779) Railliet & Henry, 1915. A. head showing cuticular elevation, ventral view; B. ventriculus and ventricular appendix, lateral view; C. male, posterior end, lateral view. (Redrawn from J. D. Smith 1984 a)