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 annulatus Margolis, 1960 Synonym: Cucullanus of Arai (1967 partim ) Description (after Margolis 1960 ). With characteristics of the genus. Males: slender, 2.21–5.50 long, anterior end bent dorsad to varying degrees, and tail curved ventrad. Head slightly swollen, 0.12–0.18 wide. Body narrows behind head towards mid-oesophageal region then widens again to 0.10–0.25 just behind oesophagus. Body tapers gradually from post-oesophageal region to cloaca and then abruptly to pointed extremity; tail 0.083–0.13 long. Cuticle, 0.002–0.005 thick, appears devoid of transverse striations in posterior half, and very fine striations are barely discernible about mid-length of body, more anteriorly striations become more definite and farther apart; ventrally from a short distance posterior to the oesophago-intestinal junction to the anterior oesophageal swelling they are more properly termed annulations ( Fig. 91 A). Attached to FIGURE 91. Cucullanus annulatus Margolis, 1960 . A. cuticle of ventral oesophageal region; B. male, anterior end, ventral view; C. male, posterior end, pre-cloacal sucker, lateral view; D. female, vulvar region, lateral view. (Redrawn from Margolis 1960) cuticular collar surrounding mouth is a continuous membranous flange with many small teeth on internal face. Head with two pairs of cephalic papillae and one pair of lateral amphids. Internally there is a chitinous framework around mouth opening. Oesophagus 0.43–0.70 long, enlarged anteriorly, narrows at midlength then expands again to a swelling less pronounced than the anterior one ( Fig. 91 B). Two-lobed valve projects from oesophagus into intestine. Intestine opens into short rectum which receives ejaculatory duct to form a cloaca. Nerve ring 0.21–0.30 from anterior end. Lateral cervical papillae 0.026–0.097 anterior to oesophago-intestinal junction. Excretory pore 0.057–0.17 behind oesophagus. Testis originates at about level of anterior margin of pre-cloacal sucker, follows straight course anteriorly then turns back on itself to join seminal vesicle. Pre-cloacal sucker in lateral view appears as fan-shaped group of muscles that when contracted take the form of cup-shaped sucker; it is 0.14–0.29 long and its posterior margin is 0.18–0.37 in front of cloaca. Eleven pairs of caudal papillae. Slender spicules, 0.47–0.76 long, pointed distally and slightly enlarged proximally ( Fig. 91 C). Gubernaculum 0.065–0.085 long. Females: egg-bearing specimens 5.16–9.43 long. Dorsal flexure of head not as pronounced as in males. Width at head and posterior end of oesophagus 0.12–0.15 and 0.15–0.21 respectively. Tail pointed, 0.15–0.24 long. Cuticle 0.004–0.008 thick. Cuticular annulations, mouth and associated structures like those of males. Nerve ring 0.28–0.33 from anterior end. Lateral cervical papillae 0.07–0.16 anterior to posterior end of oesophagus. Another pair of lateral papillae occurs about mid-length of the tail. Excretory pore 0.10–0.29 posterior to oesophagus. Vulva, overhung by prominent anterior lip, 3.1–6.1 from anterior end ( Fig. 91 D). Vagina directed anteriorly joins divergent uteri. Eggs, thin-shelled, 0.072–0.085 x 0.042–0.050. Site: intestinal lumen Hosts: Microstomus pacificus (4); Parophrys vetulus (1, 4); Platichthys stellatus (2, 3); Distribution: Pacific Records: 1. Margolis 1960 ; 2. Arai 1967a ; 3. Arai 1969 ; 4. Kabata & Whitaker 1984