Rhabdochona catostomi Kayton, Kritsky & Tobias, 1979

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 70

Rhabdochona catostomi Kayton, Kritsky & Tobias, 1979

Description (after Kayton et al. 1979). With characteristics of the genus. Body filiform, males smaller than females. Caudal end conical with terminal spike. Mouth with two bilateral rudimentary pseudolabia, two large bilateral amphids, outer circle of cephalic papillae (inner circle apparently absent). Prostom funnel-shaped, lacking basal teeth, its inner wall with 10 longitudinal cuticular ridges terminating in anterior teeth. Cuticle lines entire vestibule. Oesophagus with anterior muscular and wider posterior glandular regions. Deirids small, bifurcate, lying slightly anterior to mid-vestibule.

Males: body 8.9–14.3 long, 0.173–0.211 maximum width. Prostom 0.022–0.034, vestibule 0.134–0.174, muscular oesophagus 0.336–0.372, and glandular oesophagus 3.5–4.8 long. Deirids 0.076–0.085, nerve ring 0.204–0.238, and excretory pore 0.484 from anterior end. Tail 0.336–0.392 long, curved ventrally. Caudal alae absent. Subventral caudal papillae variable in number, 8 or 9 pre-cloacal, and 5 post-cloacal pairs ( Fig. 44 A). Left spicule 0.546–0.562 long, slender, with ventral groove, its tip with ventral barb, bifurcate. Right spicule 0.151– 0.154 long, with reflected distal barb ( Fig. 44 B). Length ratio of right to left spicule 1:3.62 to 1:3.65.

Females: body 15.3–16.7 long, 0.248–0.292 maximum width. Prostom 0.028–0.031, vestibule 0.154–0.176, muscular oesophagus 0.375–0.417, and glandular oesophagus 4.97–6.10 long. Deirids 0.090–0.097 and nerve ring 0.227–0.284 from anterior end [position of excretory pore not stated]. Tail 0.227–0.280 long, usually straight ( Fig. 44 C). Vulva post-equatorial comprising a transverse slit surrounded by elevated labia. Mature eggs ellipsoidal, embryonated, “poles usually with complex elongate filaments”, measuring 0.031–0.036 x 0.020–0.024 ( Fig. 44 D). Site: intestine

Host: Catostomus catostomus

Distribution: Alberta

Record: Kayton et al. 1979

Figures

FIGURE 44. Rhabdochona catostomi Kayton, Kritsky & Tobias, 1979. A. male, posterior end, lateral view; B. right spicule, lateral view; C. female, posterior end, lateral view; D. mature egg. (Redrawn from Kayton et al. 1979)