1	Odontostyle with a convex stiffening piece	2
	Odontostyle without stiffening piece	4
2	Stiffening piece ventral; ovary prevulval	Dorella Jairajpuri, 1964
	Stiffening piece dorsal; ovary postvulval	3
3	Labial framework sclerotized	Margollus Peña-Santiago, Peralta & Siddiqi, 1993
	Labial framework not sclerotized	Tylencholaimellus Cobb in Cobb, 1915
4	Odontophore simple without basal knobs	5
	Odontophore with distinct basal knobs	6
5	Lip region offset; basal part of pharynx cylindrical, expanded at posterior one-third	Paratylencholaimus gen. nov.
	Lip region continuous; basal part of pharynx pyriform, much shorter	GoferusJairajpuri & Ahmad, 1992
6	Female didelphic-amphidelphic	Phellonema Thorne, 1964
	Female monodelphic-opisthodelphic	7
7	Tail filiform	Oostenbrinkella Jairajpuri, 1965
	Tail short, rounded	Doryllium Cobb, 1920