Salvelinema walkeri ( Ekbaum, 1935 ) Margolis, 1967

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 walkeri ( Ekbaum, 1935) Margolis, 1967

Synonym: Cystidicola walkeri Ekbaum, 1935

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

Males (from Oncorhynchus kisutch ): 16.89–20.19 long, 0.371–0.412 maximum width. Vestibule including prostom 0.180–0.208, muscular oesophagus 0.383–0.539, and glandular oesophagus 1.510–1.870 long. Deirids, nerve ring and excretory pore 0.310–0.362, 0.383–0.461 and 0.635–0.679, respectively, from anterior end ( Fig. 64 B). Caudal alae and ventral pre-cloacal ridges well developed. Precloacal papillae: 18 to 26 pairs of subventral papillae arranged in couples. Post-cloacal papillae: six pairs of single papillae. Left spicule slender, 1.140–1.170 long, proximal end broad, distal tip sharply pointed. Right spicule short, boat-shaped, 0.152–0.192 long, proximal end blunt, distal end rounded. Tail 0.310–0.362 long ( Fig. 64 C).

Females (from O. kisutch ): gravid worms 18.150–29.030 long, 0.453–0.597 maximum width. Vestibule including prostom 0.136–0.220, muscular oesophagus 0.365–0.531, and glandular oesophagus 1.470–1.840 long. Deirids, nerve ring and excretory pore 0.246–0.400, 0.296–0.487, and 0.661–0.809, respectively, from anterior end. Tail conical, 0.357–0.409 long, with rounded tip ( Fig. 64 D). Vulva in anterior half of body, 30–40% of body length. Vagina directed posteriorly from vulva. Uterus amphidelphic. Mature eggs oval, thick-walled, larvated, 42– 54 µm x 20–24 µm; one pole with small plug and two thread-like filaments each about 360 µm long ( Fig. 64 E). Site: swim bladder

Hosts: Oncorhynchus clarkii (6); Oncorhynchus keta (4, 6); Oncorhynchus kisutch (1, 2, 3, 4, 5); Oncorhynchus

tshawytscha (5)

Distribution: Pacific

Records: 1. Ekbaum 1935; 2. Margolis 1967a; 3. Margolis 1967b; 4. Margolis & Kabata 1967; 5. Godfrey 1968; 6.

Margolis & Moravec 1982

Figures

FIGURE 64. Salvelinema walkeri (Ekbaum, 1935) Margolis, 1967. A. en face view; B. male, anterior end, lateral view; C. male, posterior end, lateral view; D. gravid female, tail, lateral view; E. mature egg. (A. redrawn from Margolis & Kabata 1967; B. to E. redrawn from Moravec & Nagasawa 1999 b)