Genus Leidynema Schwenk in Travassos, 1929

Generic diagnosis. Female: Cephalic extremity formed by two annules. Lateral alae present. Eggs large, elongate and crescent-shaped. Female tail long, filiform or attenuated. Oesophageal corpus divided into narrow anterior and broad posterior portions of roughly equal length, isthmus short, and bulb spherical. Intestine with blind diverticulum. Vulva near midbody.

Male: Cephalic extremity formed by single expanded annule. Lateral alae present or absent. Spicule present or absent. Caudal extremity in males abruptly truncate with or without short terminal spine (spine-like process on its ventral side) or with several protuberances. Caudal papillae 3–5 pairs.