A new species and a new record of the ant genus Ooceraea Roger, 1862 (Hymenoptera: Formicidae: Dorylinae) from Thailand

Currently, 16 species of the genus Ooceraea Roger, 1862 are known from the Oriental, Australian and Oceanian realms, but no identified species have ever been recorded from Thailand. Here Ooceraea siamensis sp. n. is described from Thailand based on the worker and dealate queen. The new species is most similar to O. biroi (Forel, 1907), a species widely distributed across tropical and subtropical regions of the world, but can be distinguished from the latter by postpetiole slightly longer than broad in dorsal view (clearly shorter than broad in O. biroi), by foveae on first gastral tergite and sternite denser and coarser (weak in O. biroi), and by smaller size (head width in new species 0.33–0.38 mm while in O. biroi 0.46–0.49 mm). The type series of the new species was collected from a colony in soil and partly in a coconut seed. Ooceraea duadridentata Yamada, Luong et Eguchi, 2018 is recorded from Thailand for the first time.