Rhabdochona decaturensis Gustafson, 1949

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 73

Rhabdochona decaturensis Gustafson, 1949

Description (after Gustafson 1949, and Moravec & Arai 1971). With characteristics of the genus. Small, slender, worms, attenuated at both ends. Pseudolabia rudimentary. Buccal cavity heavily sclerotized, funnel-shaped prostom containing 14 minute teeth projecting anteriorly from longitudinal ridges; four minute teeth at base of prostom ( Fig. 46 A). Oesophagus relatively long, divided into anterior muscular and posterior glandular portions. Deirids very small, simple, lateral, opposite mid-portion of buccal cavity.

Males (measurements of a paratype according to Moravec & Arai (1971) in parentheses): 6.8–8.0 long (13.29), 0.085–0.100 (0.132) maximum width. Prostom 0.015–0.017 (0.018), “total stoma” 0.096–0.110 (vestibule including prostom 0.120), muscular oesophagus 0.21–0.27 (0.255), glandular oesophagus 1.70–2.0 (3.52), and tail 0.25–0.31 (0.296) long, with terminal cuticular spike. Nerve ring 0.140–0.170 (0.180) and excretory pore 0.210– 0.250 (0.273) from anterior end. Left spicule relatively long at 0.830–1.025 (1.074), with conical distal tip, not bifurcated; spicule shaft representing 73% of entire length. Right spicule 0.075–0.100 (0.090) long, scoop-shaped, with reflected barb near tip on left side. Length ratio of right to left spicule 1:10.25 to 1:11.93. About eight (seven) pairs of pre-cloacal papillae, of which seven pairs are subventral, and one pair sublateral. Six (six) pairs of postcloacal papillae, of which the 2nd pair is sublateral, the others subventral ( Fig. 46 B).

Females (measurements of a paratype according to Moravec & Arai (1971) in parentheses): 9.2–13.4 (21.25) long, 0.093–0.160 (0.198) maximum width. Prostom 0.016–0.025 (0.024), “total stoma” 0.090–0.110 (vestibule including prostom 0.120), muscular oesophagus 0.217–0.320 (0.299), glandular oesophagus 1.92–2.6 (4.38), and tail 0.16–0.23 long (0.165) with cuticular terminal spike ( Fig. 46 C). Nerve ring 0.150–0.170 (0.183) and excretory pore 0.236–0.257 (0.270) from anterior end. Eggs embryonated when laid, ovoid, 0.031–0.038 x 0.015–0.023, bearing no filaments.

Site: intestine

Hosts: Luxilus cornutus (2, 3); Notropis hudsonius (1, 2, 3); Noturus flavus (1); Noturus gyrinus (1) Distribution: Ontario

Records: 1. Dechtiar & Christie 1988; 2. Dechtiar & Lawrie 1988; 3. Dechtiar et al. 1988

Figures

FIGURE 46. Rhabdochona decaturensis Gustafson, 1949. A. female, anterior end, dorsal view; B. male, posterior end, lateral view; C. female tail, lateral view. (Redrawn from Moravec & Arai 1971)