Truttaedacnitis clitellarius (Ward & Magath, 1917) 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 : 152-153

Truttaedacnitis clitellarius (Ward & Magath, 1917) Petter, 1974

Synonym: Cucullanus clitellarius Ward & Magath, 1917

Description (after Choudhury & Dick 1996a). With characteristics of the genus. Body moderately robust, cephalic end rounded, cuticle with transverse striations. Posterior part of body often curved ventrally. Narrow lateral alae beginning in cervical region, terminating at anal region. Mouth opening spindle-shaped, with three conspicuous papillae on either side—the central one likely an amphid. Mouth opening bordered by transparent cuticular collarette bearing weak longitudinal rib-like structures (“teeth”). Inner circle of three small papillae present. Two bud-shaped deirids, one on either side, often asymmetrical, adjacent to lateral alae, and posterior to nerve ring. Tail conical, gently tapering, bearing mucron. Hemizonid posterior to nerve ring. Oesophagus muscular, clavate, expanded anteriorly to form pseudobuccal capsule. Bilaterally symmetrical cephalic plates present, separated by narrow sutures and attached to thickened cuticular plates of pseudobuccal capsule ( Fig. 86 C). Oesophageal lumen lined by cuticle, each side of triradiate lumen thickened to give appearance of “longitudinal rods” embedded into oesophageal musculature. Oesophago-intestinal junction guarded by cuticular folded valve. Excretory pore at about mid-level of pseudobuccal capsule ( Fig. 87 A). Excretory duct long, cuticular, extending posteriorly along ventral body wall past nerve ring to first half of oesophagus, with prominent nucleus present immediately posterior to base of excretory duct ( Fig. 87 A).

Males: 13.5 (9.6–16.9) long; maximum width 0.40 (0.24–0.59). Nerve ring 0.585 (0.526–0.640) from anterior end. Oesophagus 1.35 (1.10–1.55) long. Tail 0.428 (0.301–0.564) long. Single testis originating posteriorly, extending anteriorly and looping back on itself. Posterior pre-cloacal sucker bordered by radially situated muscle bands, 1.70 (1.25–2.10) from posterior end ( Fig. 87 B). Spicules equal or slightly sub-equal, gouge shaped with median serrated margins; left spicule 1.12 (0.90–1.30) long, right one 1.14 (0.87–1.35) long. Gubernaculum with Y-shaped sclerotized body, 0.139 (0.101–0.172) long. Eleven pairs of sessile caudal papillae: four pairs pre-cloacal, one pair ad-cloacal, and six pairs post-cloacal, of which one pair are phasmids. Median papilla immediately anterior to anterior margin of cloacal opening ( Fig. 87 B).

Females: 15.1 (9.9–18.6) long; maximum width 0.43 (0.33–0.53). Nerve ring 0.613 (0.564–0.677) from anterior end. Oesophagus 1.42 (1.15–1.60) long. Tail 0.380 (0.245–0.498) long. Ovaries coiled. Anterior ovary at level of, or posterior to, oesophago-intestinal junction, in anterior third of body. Posterior ovary in posterior fifth of body ( Fig. 87 C). Oviducts extending beyond vulvar region, reflexing and giving rise to thin-walled uteri containing eggs. Vulval opening a transverse slit. Eggs ovoid, thin-shelled, 0.067 x 0.041–0.079 x 0.049.

Site: intestinal lumen

Host: Acipenser fulvescens

Distribution: Canada, Central Canada, Hudson Bay Drainage, Manitoba, Ontario, Saskatchewan Records: Bangham & Hunter 1939 (ON); Bangham 1951 (ON); Bangham 1955 (ON); Anthony 1974 (ON); Dechtiar & Christie 1988 (ON); Choudhury et al. 1990 (MB, SK); Swanson et al. 1991 (MB); Choudhury & Dick 1993 (CC); Choudhury & Dick 1996a (MB, SK); Choudhury & Dick 1996b (CA); Choudhury & Dick 1998 (HBD)

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)