Ascarophis filiformis Polyanski, 1952

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 86-90

Ascarophis filiformis Polyanski, 1952

Description (after Appy 1981). With characteristics of the genus.

Males: 12.4 (9.0–14.7) long, 0.105 (0.077–0.130) wide at vas deferens. Muscular oesophagus 0.343 (0.260– 0.403) and glandular oesophagus 2.117 (1.445–2.864) long. Deirids, nerve ring and excretory pore 0.175 (0.140– 0.209), 0.219 (0.185–0.258) and 0.325 (0.264–0.367), respectively, from anterior end ( Fig. 54 A). Tail 0.158 (0.125–0.189) long. Right spicule 0.109 (0.094–0.129) long, spicule arcuate, notched distally. Left spicule 0.328 (0.271–0.392) long, tubular, divided into proximal shaft and blade. Ratio of left to right 1:3.0 (1:2.5 to 1:3.5). Area rugosa with about 11 longitudinal rows of cuticular elevations. 10 pairs caudal papillae: two double pairs precloacal, six pairs post-cloacal; 5th post-cloacal pair relatively small, ventral to 6th pair. Caudal alae narrow. Phasmids behind last pair post-cloacal papillae ( Fig. 54 B).

Females: 25.1 (19.3–35.9) long, 0.160 (0.112–0.207) wide at vulva. Muscular oesophagus 0.386 (0.330–0.462) and glandular oesophagus 2.606 (1.845–3.424) long. Deirids, nerve ring, excretory pore and vulva 0.186 (0.143– 0.228), 0.228 (0.179–0.265), 0.340 (0.258–0.415) and 12.7 (9.5–18.3), respectively, from anterior end. Tail 0.090 (0.058–0.120) long ( Fig. 54 C). Eggs 0.047 (0.042–0.050) x 0.031 (0.028–0.035) with two filaments arising from prominent knob at one pole ( Fig. 54 D).

[For comments on A. filiformis see page 90–91]

Site: stomach

Hosts: Boreogadus saida (9); Gadus morhua (1, 2, 3, 4); Hippoglossus stenolepis (7, 8); Liparis dennyi (5); Reinhardtius hippoglossoides (6)

Distribution: Atlantic, Nunavut, Pacific

Records: 1. Redkozubova 1976 (AT); 2. Linkletter et al. 1977 (AT); 3. Appy 1981 (AT); 4. Appy & Burt 1982 (AT); 5. Ko 1986 (PA); 6. Arthur & Albert 1994 (AT); 7. Blaycock 1996 (PA); 8. Blaycock et al. 1998a (PA); Køie 2009 (NU)

Ascarophis morrhuae van Beneden, 1871

Description (after Ko 1986). With characteristics of the genus.

Males: 5.9 (5.1–7.2) long, 0.028 (0.026–0.029) wide at nerve ring. Buccal cavity 0.097 (0.086–0.108) long ( Fig. 55 A). Muscular oesophagus 0.271 (0.226–0.297) and glandular oesophagus 1.75 (1.34–2.43) long. Nerve ring 0.134 and excretory pore 0.242 from anterior end. Four pairs pre-cloacal, and six pairs post-cloacal papillae. Left spicule 0.765 (0.740–0.790), right spicule 0.098 (0.095–0.100) long ( Fig. 55 B). Tail 0.105 (0.084–0.134) long.

Females: 10.8 (8.5–12.7) long, 0.036 (0.031–0.041) wide at nerve ring. Buccal cavity 0.098 (0.085–0.115) long. Muscular oesophagus 0.246 (0.216–0.288) and glandular oesophagus 1.9 (1.1–2.3) long. Nerve ring 0.140 (0.113–0.178) and excretory pore 0.212 (0.161–0.240) from anterior end. Vulva 5.3 (4.7–6.0) from posterior end. Uterus extends from region of glandular oesophagus almost to tail tip. Tail 0.116 (0.072–0.146) long with knoblike tip ( Fig. 55 C). Embryonated eggs 0.036 (0.026–0.046) x 0.024 (0.022–0.026) with one polar plug bearing two filaments although, according to Ko (1986), eggs in the posterior extension of the uterus apparently lack filaments ( Fig. 55 C).

[For comments on A. morrhuae see below]

Site: alimentary tract

Hosts: Alosa sapidissima (4); Anarhichas lupus (3); Gadus morhua (2); Gasterosteus aculeatus (1);

Glyptocephalus cynoglossus (3)

Distribution: Atlantic, Labrador, Newfoundland

Records: 1. Hanek & Threlfall 1970a (AT, LB, NL); 2. Gaevskaya & Umnova 1977 (AT); 3. Zubchenko 1980 (AT);

4. Hogans et al. 1993 (AT)

Figures

FIGURE 54. Ascarophis filiformis Polyanski, 1952. A. male, anterior end, lateral view; B. male, posterior end, lateral view, arrow indicates left-hand pair 5 th and 6 th post-caudal papillae; C. female, posterior end, lateral view; D. egg from uterus. (Redrawn from Appy 1981)

FIGURE 55. Ascarophis morrhuae van Beneden, 1871. A. anterior end, lateral view; B. male, posterior end with short (right) spicule, arrows indicate structures that are “ possibly the phasmids ” [sic]; C. female, posterior end showing extent of uterus, eggs evidently lacking polar filaments. (A. and B. redrawn from Berland 1961; C. redrawn from Ko 1986)