Philonema Kuitunen-Ekbaum, 1933

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 54

Philonema Kuitunen-Ekbaum, 1933

Generic diagnosis (after Moravec 2013). Philometridae . Body thread-like, anterior end rounded, posterior end conical. Cuticle smooth. Cephalic papillae present or absent. Oesophagus short, posterior half expanded and containing multinucleate oesophageal gland. Females very much larger than males. Male tail coiled; cloaca remote from tail tip. Spicules simple, equal. Gubernaculum absent. Vulva and anus of gravid worms atrophied. Ovaries amphidelphic. Viviparous. Parasitic in body cavity and tissues of fishes.

Comments: Adamson et al. (1992) distinguished Philonema agubernaculum from Oncorhynchus mykiss and P. oncorhynchi from O. nerka on the basis of DNA restriction fragment length differences but did not provide morphological details. According to Moravec & Nagasawa (1999) the three recognized species of Philonema from salmonids ( P. agubernaculum , P. oncorhynchi and P. sibirica ) are inadequately described, especially regarding male caudal morphology, and cannot be distinguished one from another on the basis of the morphological features given in existing descriptions. For these reasons a key to distinguish P. agubernaculum from P. oncorhynchi has not been attempted here.