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 Pseudodelphis oligotti , Adamson & Roth 1990 Description of P. oligocotti (after Adamson & Roth 1990 ). With characteristics of the genus. Long, slender worms. Head end rounded, slightly wider in median than lateral view ( Fig. 28 A). Mouth opening subtriangular, dorsoventrally elongate, surrounded by inner ring of six and outer ring of eight papillae. Papillae of inner ring similar; those of outer ring arranged in four pairs of which the more median element of each pair is smaller. Buccal capsule a simple cuticularized ring surrounded by oesophageal tissue. Oesophagus slightly swollen at anterior end, and comprising anterior muscular and posterior glandular portion. Nerve ring and hemizonid prominent. Excretory pore inconspicuous, leading by slender tubular duct to ventral excretory cell just anterior to glandular oesophagus. Deirids in form of small digitiform projections between level of nerve ring and excretory pore. The following measurements are means for nine male and eight female P. oligocotti , with measurements of types in parentheses. Males: 16.28 (18.0) long; maximum width 0.128 (0.125). Muscular oesophagus 0.561 (0.457) and glandular oesophagus 1.054 (0.898) long. Nerve ring 0.294 (0.279), excretory pore 0.416 (0.417), and anterior extremity of testis 2.793 (1.97) from anterior end ( Fig. 28 B). Spicule 0.064 (0.070) and tail 0.205 (0.218) long. Testis unflexed, extending posteriorly as broad tube filled with developing sperm. Tail subconical with anus elevated on slightly developed genital cone. Two pairs pre-cloacal, two pairs ad-cloacal, and four pairs post-cloacal caudal papillae (occasionally ad-cloacal pairs number three on one side, and post-cloacal five on one side). Cuticular prominence on anterior anal lip with 1 median pre-cloacal papilla. Phasmids between 1st and 2nd post-cloacal papilla pair. Tail conical with rounded end, coiled in a dextral spiral in more mature worms ( Fig. 28 C). Gravid females: 26.87 (32.1) long [none contained eggs with 1st -stage larvae]; maximum width 0.169 (0.140). Muscular oesophagus 0.618 (0.704) and glandular oesophagus 1.490 (1.677) long. Nerve ring 0.274 (0.311), excretory pore 0.362 (0.416), and vulva 2.149 (2.661) from anterior end. Vagina 5.576 (3.465) long. Blind end of ovary 1.297 (1.464) from anus. Tail subconical with rounded end, 0.253 (0.279) long. Didelphic. Vagina in region of base of oesophagus, extends posteriorly to join with anterior and posterior uteri ( Fig. 28 D). Anterior uterus ends blindly about 0.500 posterior to base of oesophagus. Posterior uterus extends posteriorly to join oviduct and ovary. Sites: body cavity, mesenteries Hosts: Apodichthys flavidus (3); Artedius lateralis (3); Gasterosteus aculeatus (3); Gobiesox maeandricus (2, 3); Leptocottus armatus (2, 3); Oligocottus maculosus (1, 2, 3); Pholis laeta (2, 3); Pholis ornata (2, 3); Syngnathus leptorhynchus (2, 3) Distribution: Pacific Records: 1. Adamson & Roth 1990 ; 2. Bennett & Adamson 1994 ; 3. Bennett & Adamson 2004