Rhabdochona rotundicaudatum Byrne, 1992

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 79

Rhabdochona rotundicaudatum Byrne, 1992

Description (after Byrne 1992a). With characteristics of the genus. General characteristics: see those for R. cascadilla above.

Male paratypes (means with ranges in parentheses): body 5.8 (5.0–6.7), prostom 0.018 (0.017–0.023), vestibule 0.090 (0.081–0.100), muscular oesophagus 0.224 (0.188–0.251) and glandular oesophagus 1.6 (1.2–1.9) long. Small bifurcate deirids 0.051 (0.033–0.057), nerve ring 0.133 (0.127–0.137) and excretory pore 0.200 (0.195–0.208) from anterior end. Caudal papillae digitiform: 18 to 21 pre-cloacal and 11 to 13 post-cloacal, mostly subventral. Phasmids minute, located just distal to most posterior pair of caudal papillae. Left spicule 0.388 (0.342– 0.421), its alate portion (blade) 0.183 (0.0.159–0.196) long. Right spicule 0.092 (0.087–0.101) long, relatively stout, with dorsal projecting barb at distal end and a bulbous, convex proximal end ( Fig. 50 B). Length ratio of right to left spicule 1:3.93 to 1:4.22. Tail 0.306 (0.266–0.365) long, tapering and ending in a rounded tip ( Fig. 50 A).

Female paratypes (means with ranges in parentheses): body 10.6 (8.9–13.4), prostom 0.026 (0.023–0.028), vestibule 0.107 (0.097–0.120), muscular oesophagus 0.278 (0.261–0.290) and glandular oesophagus 2.27 (2.08– 2.54) long. Deirids 0.066 (0.060–0.076), nerve ring 0.158 (0.146–0.179) and excretory pore 0.233 (0.212–0.265) from anterior end. Vulva located near midpoint of body, 6.0 (4.9–7.3) from anterior end. Phasmids minute, posterior to midpoint of tail. Eggs ovoid, smooth, without filaments or floats, 0.023 (0.023–0.024) x 0.038 (0.036– 0.039). Tail 0.215 (0.188–0.241) long, tapering and ending in a rounded tip ( Fig. 50 C).

Note: Byrne (op. cit.) also provided measurements for the male holotype and female allotype of R. rotundicaudatum .

Site: intestine

Hosts: Ambloplites rupestris (1, 2); Ameiurus nebulosus (1, 2); Etheostoma caeruleum (1, 2); Luxilus cornutus (1,

2); Nocomis biguttatus (1, 2); Nocomis micropogon (2); Semotilus atromaculatus (1, 2)

Distribution: Ontario

Records: 1. Byrne 1992 a (ON); 2. Byrne 1992b (EX, ON)

Figures

FIGURE 50. Rhabdochona rotundicaudatum Byrne, 1992. A. male, posterior end, lateral view; B. right spicule, lateral view; C. female, posterior end, lateral view. (Redrawn from Byrne 1992 a)