Pharurus pallasii (Van Beneden, 1870) Arnold & Gaskin 1975

• Main Authors: Arai, Hisao P., Smith, John W.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2016
• Subjects: Biodiversity; Taxonomy; Animalia; Nematoda; Chromadorea; Rhabditida; Pseudaliidae; Pharurus; Pharurus pallasii; Beluga; Beluga*; Delphinapterus leucas
• Online Access: https://doi.org/10.5281/zenodo.5627017; http://treatment.plazi.org/id/038FB248FF1EFF0689B9C5BE221F9C1B

* Pharurus pallasii (Van Beneden, 1870) Arnold & Gaskin, 1975 Preamble: Pharurus pallasii matures in the cranial sinuses, middle ears, and Eustachian tubes of beluga whales ( Delphinapterus leucas ) in Canadian and other waters. Some 1st -stage larvae of P. pallasii intubated by Houde et al. (2003) into the stomach of Canadian-caught American plaice ( Hippoglossoides platessoides ) and Arctic sculpins ( Myoxocephalus scorpioides ) moulted to 2nd stage in the intestinal wall of both fish species. A description of 1st - and 2nd -stage larvae of P. pallasii is provided here although evidence that fishes serve as intermediate hosts of the species in Canadian waters appears to be lacking. First-stage larvae (measurements in µm): 295±21 long, 15±1 wide (Fig. 102 A). Oesophagus 134±8 long. Nerve ring 62±5, excretory pore 66±7, and genital primordium 176±7 from anterior end. Tail 37±7 long, delicate, ending in sharp point. Second-stage larvae (measurements in µm): 364±21.3 long, 12 ±1 wide, 2nd -stage larvae retain cuticle of the 1st stage (Fig. 102 B). Oesophagus 166±30 long. Nerve ring 64±6, excretory pore 69±5, and genital primordium 212±34 from anterior end. Tail 33±7 long, resembles that of the 1st stage. Site: intestinal wall Hosts: Hippoglossoides platessoides (EX); Myoxocephalus scorpioides (EX) Distribution: Quebec Record: Houde, Measures & Huot 2003 Published as part of Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, pp. 1-274 in Zootaxa 4185 (1) on pages 176-177, DOI:10.11646/zootaxa.4185.1.1, http://zenodo.org/record/165530