Cosmocephalus obvelatus (Creplin, 1825) Seurat, 1919

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 115

* Cosmocephalus obvelatus (Creplin, 1825) Seurat, 1919

Description (after Wong & Anderson 1982). In the apparent absence of a description of L3 from fishes the

following is based on Wong & Anderson’s (1982) account of L3 from experimentally infected amphipods. L3 are

2.05 (1.63–2.40) long, and 0.071 (0.058–0.095) wide. Head with two triangular pseudolabia and four submedian

cephalic papillae ( Fig. 69 A). Amphids small. Buccal cavity long and narrow but expanded in oral region. Pair of

inconspicuous deirids immediately behind nerve ring. Excretory pore opens 0.16 (0.14–0.19) from anterior end

( Fig. 69 B). Total oesophagus [muscular plus glandular portions] 1.15 (0.99–1.40) long. Rectum tubular with thick

cuticle. Tail tip rounded. Pair of large phasmids subventrally ( Fig. 69 C). Genital primordium of males a simple tube

lying free in pseudocoelom; that of females a similar tube but attached to body wall by vaginal primordium ( Fig.

69D).

Site: mesenteries

Hosts: Apeltes quadracus (2); Carassius auratus (1); Cottus sp. (1); Fundulus heteroclitus (3); Gasterosteus aculeatus (1, 2); Notropis hudsonius (1); Notropis sp. (1); Oncorhynchus mykiss (1); Osmerus mordax (1); Pungitius pungitius (2, 3); Semotilus atromaculatus (1)

Distribution: Nova Scotia, Ontario

Records: 1. Wong & Anderson 1982 (EX, ON); 2. Marcogliese 1992b (NS); 3. Marcogliese 1995b (NS)

Figures

FIGURE 69. * Cosmocephalus obvelatus (Creplin, 1825) Seurat, 1919. A. L 3, head, dorso-ventral view; B. L 3, anterior end, lateral view; C. L 3, posterior end, lateral view; D. female L 3, genital primordium, lateral view. (Redrawn from Wong & Anderson 1982)