Guide to the Parasites of Fishes of Canada Part V: Nematoda Author Arai, Hisao P. Author Smith, John W. text Zootaxa 2016 4185 1 1 274 journal article 10.11646/zootaxa.4185.1.1 11620862-ddcf-4c01-b0d9-32867e03d74b 1175-5326 165530 0D054EDD-9CDC-4D16-A8B2-F1EBBDAD6E09 ** Philonema oncorhynchi Kuitunen-Ekbaum, 1933 Description (after Moravec & Nagasawa 1999a ). With characteristics of the genus. Body filiform, whitish in colour, cuticle smooth. Head end rounded, bearing two rings of small papillae: outer ring of four pairs of papillae, inner ring with four single papillae. Small lateral bifid amphids present ( Fig. 37 A). Mouth opening circular. Oesophagus comprises short and narrow anterior muscular portion, and longer and wider posterior glandular portion. Oesophagus enters intestine through valve. Intestine light coloured, relatively wide anterior end. Tail conical ending in sharp point. Males: body 13.91–30.16 long, and 0.206–0.412 wide. Muscular oesophagus 0.444–0.762, and glandular portion 1.218–2.162 long. Nerve ring 0.261–0.391 from anterior end ( Fig. 37 B). Excretory pore not seen. Caudal end ventrally curved. Tail 0.331–0.566 long. Spicules equal, simple, needle-like, well sclerotized, 0.188–0.396 long. Pre-cloacal papillae: nine pairs small sessile subventral papillae, plus two subventral horn-like outgrowths or papillae separated by one unpaired median papilla on anterior cloacal lip. Post-cloacal papillae: nine pairs of small subventral papillae, distance between 2nd and 3rd greater than that between 3rd and 4th pairs ( Fig. 37 C). Females (gravid worms with larvae): body 102.8–185.0 long, and 0.948–1.483 wide. Head end rounded, cephalic papillae indistinct in lateral view. Muscular oesophagus 0.433–1.092, and glandular portion 1.277–2.019 long. Nerve ring 0.252–0.453 from anterior end ( Fig. 37 D). Excretory pore not seen. Anal opening absent. Vulva and vagina atrophied. Uterus amphidelphic, occupying most of body space, containing many 1st -stage larvae; it extends anteriorly to oesophagus level ( Fig. 37 D), and posteriorly a little behind end of intestine ( Fig. 37 E). Anterior and posterior ovaries reflexed, relatively short ( Fig. 37 D,E). Larvae from uterus variable in shape and size, 0.392–0.580 long, 0.020–0.028 wide. Head end with small dorsal tooth. Tail sharply pointed ( Fig. 37 E). Sites: body cavity, mesenteries, swim bladder Hosts: Carassius auratus (25); Oncorhynchus clarkii (6); Oncorhynchus gorbuscha (9, 31); Oncorhynchus kisutch (6); Oncorhynchus mykiss (6, 16, 25); Oncorhynchus nerka (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 25, 26, 27, 28, 29, 30, 32, 33, 34, 35); Oncorhynchus tshawytscha (5, 23, 24); Salvelinus malma (6) Distribution: British Columbia , Ontario , Pacific Records: 1. Kuitunen-Ekbaum 1933a (PA); 2. Kuitunen-Ekbaum 1933b (PA); 3. Smedley 1933 (BC); 4. Kuitunen- Ekbaum 1937a (BC); 5. Margolis 1952b (PA); 6. Bangham & Adams 1954 (BC); 7. Dombrowski 1955 (BC); 8. Margolis 1956 (BC, PA); 9. Margolis 1957 (BC, PA); 10. Margolis 1963 (BC, PA); 11. Bashirullah & Adams 1966 (BC); 12. Platzer 1966 (BC); 13. Platzer & Adams 1967 (BC); 14. Ko & Adams 1969 (BC); 15. Adams 1969 (EX, BC); 16. Bell & Hoskins 1971 (BC); 17. Lewis 1973 (BC); 18. H. D. Smith 1973 (BC); 19. Adams 1974 (BC); 20. Lewis et al. 1974 (BC); 21. Bell & Margolis 1976 (BC); 22. Boyce & Yamada 1977 (BC); 23. Anon. 1978 (BC); 24. Arai & Mudry 1983 (BC); 25. Bashirullah 1983 (EX, BC); 26. Bashirullah & Adams 1983 (BC); 27. Groot et al. 1984 (BC); 28. Bailey & Margolis 1987 ((BC); 29. Wood et al. 1987 (BC); 30. Bailey et al. 1988 (BC); 31. Dechtiar & Lawrie 1988 (ON); 32. Groot et al. 1989 (BC); 33. Garnick & Margolis 1990 (BC); 34. Adamson et al. 1992 (BC); 35. Després et al. 1995 (BC)