Cystidicola Fischer, 1798

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 95

Cystidicola Fischer, 1798

Synonyms: Fissula Lamarck, 1801 ; Ophiostoma Rudolphi, 1801 ; Ancyracanthus Schneider, 1866 ; Pseudancyracanthus Skryabin, 1925 ; Comephoronema Layman, 1933

Preamble: Two species of Cystidicola are currently recognised: C. farionis and C. stigmatura . The species differ in adult and egg morphology, longevity, reproductive strategy, and host and geographical range ( Miscampbell et al. 2004). C. farionis is short lived (about one year) and occurs in Salmonidae and Osmeridae in North America and Eurasia, whilst C. stigmatura is long lived (over 10 years) and occurs exclusively in Salvelinus spp. in North America. Suggestions over the years that Canadian fishes may harbour “strains” of C. farionis or that there is a third Cystidicola species (see Miscampbell et al. 2004, and references therein) are best addressed by further morphological and molecular studies.

Generic diagnosis (after Ko & Anderson 1969). Cystidicolidae . Pseudolabia small. Mouth opening dumb-bell shaped; armed with two rows of teeth, an exterior row comprising one large ventral, one large dorsal, two prominent lateral, and numerous small teeth in the form of fine serrations, and an internal row of 16 large teeth, four in each quadrant formed by the ventral, dorsal, and lateral teeth ( Fig. 59 A). Buccal cavity long and slender. Oesophagus divided into short anterior muscular and long posterior glandular portions. Excretory pore posterior to nerve ring, near junction of muscular and glandular oesophagus ( Fig. 59 B). Vulva slightly posterior to mid–body length. Tail short. Fully developed eggs bear lateral and/or polar filaments or a pair of lateral “lobes” (“floats” or “mammillations” in litt.). Parasitic in swim bladder of fishes.

Figures

FIGURE 59. Cystidicola farionis Fischer, 1798. A. female, en face view; B. male, anterior end, lateral view; C. male, posterior end, ventral view; D. fully developed eggs with polar filaments only and with both lateral and polar filaments. (Redrawn from Ko & Anderson 1969).