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

<i>Meranoplus</i> Smith, 1853 is distributed in the Old World tropics, from Africa, Asia, New Guinea to Australia. There are four species <i>Meranoplusbicolor</i> (Guérin-Méneville, 1844), <i>M.castaneus</i> Smith, 1857, <i>M.laeviventris</i> Emery, 1889, and <i>M.mucronatus</i> Smith, 1857 previously recorded from Thailand. In the present paper, two new species of the genus, <i>M.siamensis</i> Yodprasit & Jaitrong, <b>sp. nov.</b> and <i>M.tanomtongi</i> Yodprasit & Jaitrong, <b>sp. nov.</b>, are described based on the worker caste. Additionally, <i>M.malaysianus</i> 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.