PHILOMETRIDAE

Arai, Hisao P. & Smith, John W., 2016, Guide to the Parasites of Fishes of Canada Part V: Nematoda, Zootaxa 4185 (1), pp. 1-274 : 42

Key to genera of PHILOMETRIDAE

1 Body elongate, claviform; oesophageal gland limited to middle of oesophagus............................. Clavinema

- Body cylindrical, long; oesophageal gland more or less extensive.............................................. 2

2 Dorsal oesophageal gland developed along greater posterior portion of oesophagus; anterior muscular portion more or less swollen anteriorly, without free posterior glandular appendix ; anterior ovary not rudimentary........................ 3

- Anterior muscular portion of oesophagus elongate, with two swellings separated by nerve ring, with free posterior glandular appendix ; anterior ovary rudimentary............................................................ Ichthyofilaria

3 Body of female covered with prominent cuticular bosses.......................................... Philometroides

- Body of female smooth, without cuticular bosses........................................................... 4

4 Posterior end of both sexes rounded; anus of male terminal; gubernaculum present......................... Philometra

- Posterior end of both sexes tapering to a sharp point; tail of male coiled, anus remote from tail tip; gubernaculum absent............................................................................................... Philonema