Diagnosis (modified after Gourbault & Decraemer, 1996): Epsilonematidae. Ambulatory setae present (except in Perepsilonema), slender, more or less bent and arranged in four to seven longitudinal rows. Head a slightly asymmetrical cone, truncated apically. Pharynx with muscular terminal bulb (except in Triepsilonema). Female reproductive system didelphic with ovaries antidromously reflected (anterior branch only outstretched in Leptepsilonema (partim) and both branches outstretched in Triepsilonema and in some Leptepsilonema species).
Type genus: Epsilonema Steiner, 1927.