Guide to the Parasites of Fishes of Canada Part V: Nematoda Author Arai, Hisao P. Author Smith, John W. text Zootaxa 2016 4185 1 1 274 journal article 10.11646/zootaxa.4185.1.1 11620862-ddcf-4c01-b0d9-32867e03d74b 1175-5326 165530 0D054EDD-9CDC-4D16-A8B2-F1EBBDAD6E09 Cucullanus heterochrous Rudolphi, 1802 Description (after Berland 1970 ). With characteristics of the genus. Body fairly stout and of even breadth, greatest width just behind oesophagus. Head straight or slightly bent dorsally, and only slightly swollen. Cuticle transversely striated throughout, 0.003–0.007 thick. Mouth a dorso-ventral slit. Collarette surrounding the mouth well developed, the inner face with about 50 teeth on either side. Characteristic two pairs large papillae and one pair amphids on head. Internal circle of six relatively large papillae. Dorsal half of pseudobuccal capsule wide. Peribuccal rim lies well within mouth opening. Oesophagus relatively short, straight at nerve ring level but slightly dilated just behind it ( Fig. 94 A). Males: 5.33–7.55 long; maximum width 0.17–0.22. Oesophagus 0.77–0.94 long. Nerve ring 0.31–0.38, deirids 0.69–0.75 and excretory pore 0.91–1.08 from anterior end. Pre-cloacal sucker present. Left spicule 0.78–1.08 long, right spicule 0.71–0.97 long; one spicule, usually the left one, has a screw-like tip, whilst the other is usually straight and more blunt. Both spicules carry broad alae. Gubernaculum 0.046–0.059 long. Pointed tail narrows abruptly behind cloaca. In addition to the usual 11 pairs of caudal papillae there is one large median papilla behind the cloaca ( Fig. 94 B). Females: 7.50–10.78 long; maximum width 0.21–0.29. Oesophagus 0.93–1.03 long. Nerve ring 0.37–0.42, deirids 0.82–0.96, excretory pore 1.11–1.19 and vulva 4.56–6.50 from anterior end. Protrusion (“post-cloacal lip”) behind anus ( Fig. 94 C). Eggs 0.072–0.091 x 0.042–0.049. Site: alimentary tract Hosts: Hippoglossus stenolepis (2, 3); Limanda ferrugineus (1); Pseudopleuronectes americanus (1) Distribution: Atlantic, Pacific Records: 1. Ronald 1963 (AT); 2. Blaycock 1996 (PA); 3. Blaycock et al. 1998a (PA)