Cucullanellus kanabus Walder & Arai, 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 : 168-170

Cucullanellus kanabus Walder & Arai, 1974

Synonym: Cucullanus sp. of Arai (1967, 1969 partim)

Description (after Walder & Arai 1974). With characteristics of the genus. Relatively slender worms, head not enlarged. Cuticle 0.002–0.009 thick, with fine striae visible only in larger worms. Mouth a dorso-ventral slit, transverse to body axis, surrounded by short collarette bearing many small teeth. Two lateral amphids and 4 submedian cephalic papillae present. Oesophagus with sclerotized lining, dilated anteriorly as a laterally compressed pseudobuccal capsule. Dorsally, capsule lining produced into lateral plates appearing in dorsal view as a pair of anterior horn-shaped structures and a pair of broad, blade-like structures tapering posteriorly and extending almost to nerve ring level. Anterior portion of capsule a thickened sclerotized rim with short angular block ventrally. Oesophago-intestinal valve consisting of two lateral lobes. Ventral intestinal caecum not reaching nerve ring ( Fig. 97 A). Both sexes with tapering tail.

Males: 3.05–7.48 long maximum width 0.084–0.20. Posterior end curved ventrally, tail 0.065–0.11 long. Oesophagus 0.47–0.71, and ventral intestinal caecum 0.14–0.37 long. Nerve ring 0.14–0.27 from anterior end.

Excretory pore 0.030–0.48 [sic] behind oesophagus ( Fig. 97 A). Cervical papillae anterior or posterior to posterior end of oesophagus. Two lateral papillae in mid-body region. Posterior margin of pre-cloacal sucker 0.23–0.48 from anus. Testis not convoluted, origin near level of, or posterior to, sucker, anterior extent 0.14–2.25 from oesophagus. Spicules slender, pointed, virtually equal at 0.33–0.60 (left) and 0.32–0.61 (right) long ( Fig. 97 B). Gubernaculum 0.034–0.059 long. Eleven pairs caudal papillae: three pairs pre-cloacal, subventral, distributed relatively anteriad; four pairs ad-cloacal; four pairs post-cloacal near tip of tail ( Fig. 97 B).

Females: 4.99–10.61 long; maximum width 0.12–0.27. Oesophagus 0.57–0.77, and ventral intestinal caecum 0.17–0.42 long. Nerve ring 0.22–0.27 from anterior end. Excretory pore 0.13–0.46 behind posterior end of oesophagus. Cervical and lateral papillae as in males. One pair lateral phasmids, not papillose, about one-third distance from posterior end to anus ( Fig. 97 C). Vulva in posterior half of body, 3.26–6.11 from anterior end. Vagina directed anteriorly, amphidelphic. Ovaries convoluted, anterior one extending to near oesophagus, posterior one to near anus. Eggs 0.059–0.074 x 0.034–0.058.

Site: intestinal lumen

Host: Cymatogaster aggregata

Distribution: Pacific

Records: Arai 1967b; Walder & Arai 1974; Arai & Arthur 1977; Arai et al. 1988

Figures

FIGURE 97. Cucullanellus kanabus Walder & Arai, 1974. A. male, anterior end, lateral view; B. male, posterior end, lateral view; C. female, posterior end, ventral view. (Redrawn from Walder & Arai 1974)