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 Dichelyne robustus (Van Cleave & Mueller, 1932) Mueller, 1933 Synonym: Dacnitoides robusta Van Cleave & Mueller, 1932 Description (after Van Cleave & Mueller 1932). With characteristics of the genus. Body robust, with conspicuous cuticular thickening from oral region to beyond limit of oesophagus. Prominent pair of amphids or cephalic papillae near posterior limit of oesophagus. Oesophagus 0.38–0.43 long. Ventral intestinal caecum extends anteriorly almost to buccal cavity ( Fig. 95 A). FIGURE 95. Dichelyne robustus (Van Cleave & Mueller, 1932) Mueller, 1933 . A. female, anterior end, dorsal view; B. male, posterior end, ventral view; C. female, tail, ventral view. (Redrawn from Van Cleave & Mueller 1932) Males: 4.25–4.50 long; width about 0.32. Pre-cloacal sucker absent. Four pairs of pre-cloacal and four pairs of post-cloacal papillae. One median and three pairs of lateral papillae just anterior to cloaca ( Fig. 95 B). Spicules relatively short; when withdrawn they appear tubular but when extruded are broad, ribbon-like, with frilled tips. Gubernaculum apparently absent. Females: about 5.0 long; width 0.47–0.51. Ovarian coils extend almost to anterior end of body ( Fig. 93 A). Vulva short distance behind mid-body. Anus about 0.15 from tail tip. Pair minute lateral papillae in middle of postcloacal region. Tail bears spine with “the structure of a sensory papilla” ( Fig. 95 C). Comments: the original description of D. robustus is inadequate and, according to Caspeta-Mandujano et al . (1999) , type specimens are not available in the US National Parasite Collection, Beltsville , Maryland—collections that have been transferred to the Smithsonian Institution , National Museum of Natural History ( Washington , DC, USA ). It seems that Maggenti (1971) was not first to transfer Dacnitoides robusta to Dichelyne as “ Dichelyne robusta ” [= Dichelyne robustus ]. The n.comb. appears to have been first proposed by Mueller (1933) . Site : intestinal lumen Hosts: Ameiurus melas (2); Ameiurus nebulosus (1) Distribution: Manitoba , Ontario Records: 1. Bangham 1955 (ON); 2. Choudhury & Nadler 2016 (MB)