A third species of the rare ant genus Rotastruma (Hymenoptera, Formicidae) from Cambodia, with illustrated generic diagnoses and key to species

Rotastruma epispina sp. nov., worker. 1, Mouthparts [1]; 2, Left mandible [2]; 3, Clypeus [3, 4, 5, 6]; 4, Full-face view of head [7, 8, 9, 18]; 5, Mesosoma in profile view [10, 11, 12, 18]; 6, Mesosoma in dorsal view [10, 18]. Figures in brackets correspond to diagnostic characters (Appendix 1).