Philometra cylindracea (Ward & Magath, 1917) Van Cleave & Mueller, 1934

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 46

Philometra cylindracea (Ward & Magath, 1917) Van Cleave & Mueller, 1934

Synonym: Ichthyonema cylindracea Ward & Magath, 1917

Description (after Molnar & Fernando 1975a). With characteristics of the genus.

Males: transparent, minute, 2.7 (2.5–2.8) long. Greatest width close to posterior end, 0.035 (0.031–0.041); at

nerve ring level, 0.025 (0.021–0.031). Cuticle smooth and thin. Head rounded; papillae not observed. Mouth three-

lobed. Oesophagus a muscular tube 0.615 (0.572–0.680) long, with a well-developed oesophageal gland alongside.

Intestine narrow. Tail end blunt, with two lateral papillae connected by a narrow inconspicuous membrane.

Spicules relatively short, subequal, right one 0.060 (0.049–0.071), left one 0.061 (0.049–0.075). Gubernaculum

0.038 (0.034–0.043) long, in the form of a bent chitinous plate with a spear-like posterior end ( Fig. 31 A). Females: Fully developed worms are coloured red and 97 (91–102) long. Body cylindrical, tapering slightly at

both extremities; greatest width 0.9 (0.8–1.0). Cuticle thin and smooth. Body cavity filled by uterus full of larvae.

Head rounded, with three lips and four inconspicuous papillae ( Fig. 31 B). Caudal end also rounded, showing two

small lateral papillae ( Fig. 31 C). Oesophagus 2.3 (2.0–2.9) long, muscular and forming a bulb near mouth.

Oesophageal gland very prominent with clearly visible nucleus at its centre ( Fig. 31 B). Intestine greater in width

than posterior portion of oesophagus. Vulva atrophied. Two long, thin ovaries run in opposite directions connected

by common uterine duct. Anterior ovary bent backwards near nerve ring region, the posterior one bent forwards at

terminal end of intestine. Uterus packed with vigorously moving larvae; larvae are 0.36 (0.31–0.39) long and have

rounded anterior ends and sharply attenuated tails ( Fig. 31 B,C).

Site: body cavity

Hosts: Aplodinotus grunniens (1); Perca flavescens (1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12); Salvelinus fontinalis (2, 13); Sander vitreus (1)

Distribution: Ontario, Quebec

Records: 1. Bangham & Hunter 1939 (ON); 2. Fantham & Porter 1948 (QC); 3. Bangham 1955 (ON); Tedla 1969 (ON); 4. Tedla & Fernando 1969a (ON); 5. Tedla & Fernando 1972 (ON); 7. Dechtiar 1972a (ON); 8. Molnar et al. 1974 (ON); 9. Molnar & Fernando 1975a (ON); 10. Dechtiar & Christie 1988 (ON); 11. Dechtiar & Nepszy 1988 (ON); 12. Dechtiar et al. 1988 (ON); 13. Marcogliese & Cone 1991a (QC)

Figures

FIGURE 31. Philometra cylindracea (Ward & Magath, 1917) Van Cleave & Mueller, 1934. A. male, posterior end; B. female, anterior end; C. female, posterior end. (Redrawn from Molnar & Fernando 1975 a)