Two new species and a new record of the ant genus Meranoplus Smith, 1853 (Hymenoptera, Formicidae, Myrmicinae) from Thailand.

Meranoplus Smith, 1853 is distributed in the Old World tropics, from Africa, Asia, New Guinea to Australia. There are four species Meranoplusbicolor (Guérin-Méneville, 1844), M.castaneus Smith, 1857, M.laeviventris Emery, 1889, and M.mucronatus Smith, 1857 previously recorded from Thailand. In the present paper, two new species of the genus, M.siamensis Yodprasit & Jaitrong, sp. nov. and M.tanomtongi Yodprasit & Jaitrong, sp. nov. , are described based on the worker caste. Additionally, M.malaysianus Schödl, 1998 is recorded for the first time for Thailand. A key to the Oriental and Indo-Australian species, based on the worker caste, is provided. The new species and the new record were found to nest in soil.