Salmonema ephemeridarum (von Linstow, 1872) Moravec, Santos & Brasil-Sato, 2008

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 100-102

Salmonema ephemeridarum (von Linstow, 1872) Moravec, Santos & Brasil-Sato, 2008

Synonyms: Sterliadochona ephemeridarum (von Linstow, 1872) Petter, 1974 ; Metabronema harwoodi Chandler, 1931 ; Metabronema canadense Skinker, 1931 ; Metabronema salvelini (Fujita, 1920) Baylis, 1935 ; Cystidicoloides harwoodi (Chandler, 1931) Dollfus & Campana-Rouget, 1956 ; Sterliadochona tenuissima (Zeder, 1800) Spassky & Roitman, 1957 ; Cystidicoloides tenuissima (Zeder, 1800) Rasheed, 1965 ; Cystidicoloides ephemeridarum (von Linstow, 1872) Moravec, 1981

Description (after Moravec 2013). With characteristics of the genus. Whitish, medium-sized worms with transversely striated cuticle; posterior margins of cuticular rings somewhat elevated. Pseudolabia broad, flat; each pseudolabium with dorsal and ventral lobes and a small papilla-like protrusion. Mouth opening oval, dorsoventrally flattened, with two subdorsal and two subventral elongate sclerotized plates. Mouth surrounded by two dorso-lateral and two ventro-lateral cephalic papillae, and a pair small lateral amphids. Vestibule well sclerotized, long, in lateral view forming small funnel-shaped prostom. Deirids simple, very small, at level of posterior half of vestibule. Oesophagus comprises muscular and glandular portions. Nerve ring encircling muscular oesophagus, excretory pore below nerve ring level. Males much smaller than females.

Males: 5.25–8.16 long, 0.087–0.163 maximum width. Vestibule 0.094–0.147, muscular oesophagus 0.600– 1.183, and glandular oesophagus 1.38–2.62 long. Nerve ring 0.177–0.255 and excretory pore 0.246–0.300 from anterior end ( Fig. 61 A). Posterior end usually spirally coiled, with fairly wide caudal alae. Caudal papillae: four pairs subventral pedunculate pre-cloacal papillae, and five pairs subventral pedunculate post-cloacal papillae. One pair very small ventral sessile papillae at level of last subventral pair. Area rugosa anterior to cloaca ( Fig. 61 B). Spicules unequal and dissimilar: large (left) one 0.262–0.345 long, distal end with conical cuticular membrane ( Fig. 61 C); short (right) one boat-shaped 0.081–0.140 long, with ventral cuticular ala along its entire length ( Fig. 61 D). Tail conical, 0.108–0.156 long, with rounded end.

Females: gravid worms 12.74–14.86 long, 0.244–0.313 maximum width. Vestibule 0.136–0.165, muscular oesophagus 1.36–1.50, and glandular oesophagus 2.12–3.26 long. Nerve ring 0.210–0.240 and excretory pore 0.303–0.330 from anterior end. Tail very short, rounded, 0.045–0.060 long. Vulva in posterior half of body, 8.09– 9.18 from anterior end. Uterus amphidelphic. Eggs oval, thick-walled, with smooth surface, 0.036–0.048 x 0.024– 0.030. Mature eggs contain a formed larva.

Sites: alimentary tract, swim bladder

Hosts: Anguilla rostrata (18); Coregonus artedi (42); Coregonus clupeaformis (17, 35, 41, 42, 43); Cottus asper

(10); Esox masquinongy (8, 9); Hiodon tergisus (28); Oncorhynchus clarkii (10); Oncorhynchus kisutch (10, 13, 42, 43); Oncorhynchus mykiss (7, 10, 11, 25, 30, 34, 35, 41, 43); Oncorhynchus nerka (10, 13, 43); Prosopium cylindraceum (10); Prosopium williamsoni (10); Rhinichthys cataractae (10); Salmo salar (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 29, 47); Salmo trutta (14, 16, 43); Salvelinus alpinus (6, 17, 18, 32, 37, 45); Salvelinus fontinalis (1, 2, 3, 4, 5, 7, 11, 12, 14, 16, 17, 18, 19, 20, 26, 27, 31, 36, 38, 39, 40, 41, 44, 46, 48); Salvelinus malma (10, 25, 34); Salvelinus namaycush (17, 42); Thymallus arcticus (25, 34); unspecified “dace” (8); unspecified “salmonids” (33)

Distribution: British Columbia, Central Canada, Labrador, Manitoba, New Brunswick, Newfoundland, Nova Scotia, Northwest Territories, Ontario, Prince Edward Island, Quebec

Records: 1. Skinker 1931 (QC); 2. Bangham & Hunter 1939 (ON); 3. Lyster 1940 (QC); 4. Richardson 1942 (QC); 5. Choquette 1948a (QC); 6. Choquette 1948b (QC); 7. Bangham 1951 (ON); 8. Choquette 1951b (QC); 9. Choquette 1951c (QC); 10. Bangham & Adams 1954 (BC); 11. Bangham 1955 (ON); 12. Choquette 1955 (QC); 13. Margolis 1965 (BC); 14. Pippy 1965 (NF); 15. Pippy 1967 (LB, NB, NL, PE); 16. Sandeman & Pippy 1967 (NF); 17. Hicks & Threlfall 1973 (LB); 18. Hanek & Molnar 1974 (QC); 19. Hare & Frantsi 1974 (NS); 20. Frantsi et al. 1975 (NB); 21. Hare 1975 (NB); 22. Hare & Burt 1975a (NB); 23. Hare & Burt 1975b (NB); 24. Hare & Burt 1976 (NB); 25. Anon. 1978 (BC); 26. Chinniah & Threlfall 1978 (LB); 27. Thompson & Threlfall 1978 (QC); 28. Glenn 1980 (MB); 29. Pippy 1980 (AT); 30. Anon. 1981 (BC); 31. G. A. Black 1981a (QC); 32. Dick & Belosevic 1981 (NT); 33. Margolis & Moravec 1982 (BC); 34. Arai & Mudry 1983 (BC); 35. Anon. 1984 (BC); 36. Cone & Ryan 1984 (NF); 37. Dick 1987 (NT); 38. Frimeth 1987a (NB); 39. Frimeth 1987b (NB); 40. Greenwood & Baker 1987 (ON); 41. Dechtiar & Christie 1988 (ON); 42. Dechtiar & Lawrie 1988 (ON); 43. Dechtiar et al. 1988 (ON); 44. Baggs & McT. Cowan 1989 (NF); 45. Bouillon & Dempson 1989 (QC); 46. Marcogliese & Cone 1991a (NB, NS, QC, LB, NL); 47. Marcogliese & Cone 1991b (NF); 48. Dubois et al. 1996 (QC)

Figures

FIGURE 61. Salmonema ephemeridarum (von Linstow, 1872) Moravec, Santos & Brasil-Sato, 2008. A. anterior end, lateral view; B. male, posterior end, ventral view; C. left spicule; D. right spicule. (Redrawn from Moravec 2013).