Genus Pseudonymus Diesing, 1857

Generic diagnosis. Female: Cephalic extremity formed by circumoral annule and expanded second annule. Oesophageal corpus clavate. Isthmus a constriction between corpus and bulb. Vulva near posterior-third of the body. Vagina short, anteriorly directed. Gonads amphidelphic. Eggs broadly oval with filaments twisted around shell, polar egg filaments absent. Tail filiform or bluntly attenuated or conically attenuated or conical.

Male: Cephalic extremity formed by single annule. Corpus cylindrical. Caudal papillae 3–6 pairs. Spicule present or absent. Caudal appendage consists of one or two parts.