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 Raphidascaris Railliet & Henry, 1915 Synonyms: Hysterothylacium Ward & Magath, 1917 ; Ichthyascaris Wu, 1949 ;? Neogoezia Kreis, 1937 Preamble: Raphidascaris acus is the only species of the genus known from Canadian fishes. The life cycle of R. acus was discussed by J. D. Smith (1984b) and Moravec (2013) and involves predatory fishes as final hosts, and various invertebrates and fishes as paratenic or intermediate hosts. Adult and larval stages of R. acus are described below. Generic diagnosis (after Moravec 2013). Raphidascaridinae . Large nematodes, widest in midbody. Cuticle with distinct striations. Lips well developed, of complex structure. Interlabia rudimentary or absent. Excretory pore slightly behind nerve ring level. Narrow lateral alae may be present. Preventriculus muscular; ventriculus almost spherical; posteriorly directed ventricular appendix present. Intestinal caecum absent. Spicules subequal, arcuate, alate. Caudal papillae numerous. Vulva anterior to mid-length of body. Oviparous. Parasites of marine and freshwater fishes.