A new hypopterous genus and species, Omkoiana aculeata gen. n. & sp. n., from northwestern Thailand is described and diagnosed. The long median projection on the subgenital plate of the male is so far unique in Asiatic Meconematinae. O. aculeata dwells in the litter and the herbaceous layer of Tropical Mixed Deciduous Forests. It did not occur in other forest types with sparse or grass-dominated undergrowth vegetation. A rich understorey vegetation is considered important for the life habits of the new species.