Genus Crassolabium
Yeates, 1967
Diagnosis:  Body size 0.9-1.3 mm.  Cuticle smooth, sub-cuticle finely annulated.  Lip region offset, lateral lips with two thickenings in outer portion.  Odontostyle simple, dorylaimoid.  Guiding ring single.  Odontophore rod-like.  Oesophagus typical dorylaimoid type.  Vulva a transverse slit, opening into lightly cuticularised cavity.  Female reproductive system amphidelphic.   Spicules dorylaimoid; ventromedian supplements contiguous.  Tail short, dorsally convex, rounded in both sexes.

Type and only species:  Crassolabium australe  Yeates, 1967.

Remarks:  Siddiqi (1969) synonymised Crassolabium with Eudorylaimus.  Andrassy (1976) initially considered it valid but in 1986 treated it as a synonym of Thonus.
(Description- Jirajpuri and Ahmad, 1992)