Salvelinema salmonicola (Ishii, 1916) Margolis, 1966

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 105

Salvelinema salmonicola (Ishii, 1916) Margolis, 1966

Synonym: Cystidicola salmonicola Ishii, 1916

Description (after Moravec & Nagasawa 1999b). With characteristics of the genus.

Males (from Oncorhynchus mykiss ): 15.66–18.99 long, 0.288–0.474 maximum width. Vestibule including prostom 0.116–0.144, muscular oesophagus 0.444–0.487, and glandular oesophagus 1.440–1.820 long. Deirids, nerve ring and excretory pore 0.278–0.320, 0.365–0.426 and 0.609–0.705, respectively, from anterior end. Caudal alae and ventral pre-cloacal cuticular ridges well developed. Pre-cloacal papillae: 19 to 21 pairs of subventral papillae, mostly arranged in couples. Post-cloacal papillae; six pairs of single papillae (occasionally seven papillae on right side and six on left). Left spicule slender 0.960–1.050 long, proximal end broader, distal end sharply pointed. Right spicule short, boat-shaped, 0.128–0.160 long, proximal end blunt, distal end rounded. Tail 0.224– 0.264 long ( Fig. 63 B).

Females (from O. mykiss ): gravid worms 20.830–27.910 long, 0.577–0.824 maximum width. Vestibule including prostom 0.120–0.160 ( Fig. 63 A), muscular oesophagus 0.539–0.566, and glandular oesophagus 1.700– 2.130 long. Deirids, nerve ring and excretory pore 0.344–0.348, 0.409–0.522 and 0.679–0.722, respectively, from anterior end. Tail slender, 0.409–0.487 long with distal tip separated by cuticular constriction to form knob-like appendage ( Fig. 63 C). Vulva near midbody, 48–54% of body length. Vagina directed anteriorly from vulva. Uterus amphidelphic, ovaries in anterior and posterior parts of body. Mature eggs oval, thick walled, larvated, 42–50 µm x 18–20 µm; each pole with small plug and two thread-like filaments about 140 µm long ( Fig. 63 D); exceptionally there may be three filaments at one pole.

Site: swim bladder

Hosts: Oncorhynchus kisutch (1); Salvelinus malma (2, 3)

Distribution: British Columbia

Records: 1. Margolis 1966; 2. Margolis 1967a; 3. Margolis & Kabata 1967

Figures

FIGURE 63. Salvelinema salmonicola (Ishii, 1916) Margolis, 1966. A. female, anterior end, dorso-ventral view; B. male, posterior end, lateral view; C. gravid female, tail, lateral view; D. mature egg. (Redrawn from Moravec & Nagasawa 1999 b)