Truttaedacnitis truttae (Fabricius, 1794) Petter, 1974

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 156-158

** Truttaedacnitis truttae (Fabricius, 1794) Petter, 1974

Synonyms: Bulbodacnitis globosa (Zeder, 1800) Lane, 1916 ; Bulbodacnitis occidentalis Smedley, 1933 ; Bulbodacnitis truttae (Fabricius, 1794) Maggenti, 1971 ; Bulbodacnitis alpinus Mudry and McCart, 1974 ; Truttaedacnitis alpinus ( Mudry and McCart, 1974) Pybus, Uhazy and Anderson, 1978

Description (after Berland 1970, and Mudry & McCart 1974). With characteristics of the genus. Medium sized worms, cuticle moderately thick, minutely striated throughout. Head bulbous, inclined dorsally. Oral aperture bordered by cuticular collarette bearing about 100 small conspicuous “teeth”. Six cephalic papillae surround oral aperture. Pseudobuccal cavity with cephalic plates ( Fig. 86 A). Excretory pore about midway between nerve ring and oesophago-intestinal junction. Deirids located anterior to excretory pore. Tail conical, bearing button-shaped or nipple-shaped mucron (North American material) or pointed mucron (European material).

Males: 8.37–15.27 long; maximum width 0.25–0.42. Nerve ring 0.374–0.537, and excretory pore 0.584–0.931 from anterior end. Oesophagus clavate, 0.928–1.341 long. Single testis 0.36–2.04 from oesophagus base. Posterior lip of pre-cloacal sucker 0.836–1.251 from tail tip. Spicules equal, 0.455–0.537 long, not overlapping pre-cloacal sucker when fully retracted. Arrangement of caudal papillae similar to that of T. clitellarius above ( Fig. 87 B). Gubernaculum 0.107–0.134 long.

Females: 11.81–18.00 long; maximum width 0.27–0.42. Nerve ring 0.421–0.523, and excretory pore 0.612– 0.877 from anterior end. Oesophagus clavate, 1.049–1.375 long. Posterior ovary extends into tail region. Vulva raised, located 7.482–11.080 from anterior end ( Fig. 90 ). Eggs 0.044–0.054 x 0.062–0.083.

Larvae: the variety of hosts from which Truttaedacnitis truttae has been recovered and the extra-alimentary tract sites occupied (see below) suggest that larvae are present, though none appears to have been described in litt.

Sites: alimentary tract, gills, gonads, intestinal lumen, kidneys, liver, mesenteries, pyloric caeca

Hosts: Coregonus clupeaformis (13); Oncorhynchus clarkii (2); Oncorhynchus mykiss (1, 2, 7, 8, 9, 10, 11, 12, 13, 19); Oncorhynchus nerka (10, 13); Petromyzon marinus (3, 4); Prosopium cylindraceum (2); Prosopium williamsoni (2, 7, 8, 10, 11, 13, 18); Ptychocheilus oregonensis (10, 13); Salvelinus alpinus (5, 6); Salvelinus fontinalis (2, 14, 15, 16, 17, 19); Salvelinus malma (2, 8, 10, 11, 13, 19); Salvelinus namaycush (7, 8, 11, 13, 19)

Distribution: Alberta, British Columbia, New Brunswick, Ontario, Yukon Territory

Records: 1. Smedley 1933 (BC); 2. Bangham & Adams 1954 (BC); 3. Wilson 1967 (ON); 4. Wilson & Ronald 1967 (ON); 5. Mudry & McCart 1974 (YT); 6. Mudry & McCart 1976 (YT); 7. Mudry & Anderson 1977 (AB); 8. Anon. 1978 (BC); 9. Russell 1980 (BC); 10. Anon. 1981 (BC); 11. Arai & Mudry 1983 (BC); 12. Dunn et al. 1983 (BC); 13. Anon. 1984 (BC); 14. Frimeth 1986 (NB); 15. Frimeth 1987a (NB); 16. Frimeth 1987b (NB); 17. Marcogliese & Cone 1991a (NB); 18. Nener et al. 1995 (BC); 19. Choudhury & Dick 1996b (BC, NB, YT)

Figures

FIGURE 86. Truttaedacnitis spp.: heads showing cephalic plates. A. T. truttae; B. T. sphaerocephala; C. T. clitellarius; D. T. pybusae. (A., B. and C. redrawn from Choudhury & Dick 1996 b; D. redrawn and rotated from Pybus et al. 1978 a)

FIGURE 87. Truttaedacnitis clitellarius (Ward & Magath, 1917) Petter, 1974. A. male, anterior end showing excretory pore and duct, lateral view; B. male, posterior region showing pre-cloacal sucker, spicules and papillae, lateral view; C. female, posterior end showing posterior coiled ovary, rectal glands, phasmid and mucron, lateral view. (Redrawn from Choudhury & Dick 1996 a)

FIGURE 90. ** Truttaedacnitis truttae (Fabricius, 1794) Petter, 1974. Female, vulvar region, lateral view. (Redrawn from Mudry & McCart 1974)