Two remarkable new species of the genus Crassolabium Yeates, 1967 from Vietnam (Nematoda: Dorylaimida: Qudsianematidae)

Two new species of the genus Crassolabium are described from natural areas in Vietnam. Crassolabium aenigmaticum sp. nov. is characterized by its body 1.23–1.58 mm long, lip region continuous, odontostyle 17.0–19.0 μm long, neck 320.0–397.0 μm long, uterus tripartite, pars refringens vaginae with two triangular pieces separated by an intermediate sclerotized area, V?=?54–59, vulva longitudinal, tail short and rounded in both sexes, spicules 43.0–48.0 μm long, and seven to eight spaced ventromedian supplements. C. vietnamense sp. nov. can be distinguished in having body 1.55–1.88 mm long, lip region offset by constriction, odontostyle 19.5–22.0 μm long, neck 370.0–448.0 μm long, uterus very long and tripartite, pars refringens vaginae with two close together pieces, V?= 55–59, vulva transverse and usually covered with a plug, tail short and rounded in both sexes, spicules 53.0–55.0 μm long, and eight to nine spaced ventromedian supplements, two of them within the range of spicules.