Singapore Ant

Body length of workers (highly variable - Polymorphic) 1.8 - 3.5 mm. This ant is dark brown to blackish brown, and usually with a conspicuous yellow area mediobasally. A relatively large Monomorium species; Body yellowish brown to reddish brown from head to postpetiole; gaster blackish brown. Mandibles each with 4 teeth, the basalmost sometimes obscure. Eyes large, each with around 20 facets. Median paired carinae of clypeus obscure. Metanotal groove distinct. Propodeum with angulate posterodorsal border; the area of petiolar insertion carinate. Ventral outline of petiole less convex than in other species. Postpetiole 1.1 -1.2 times as long as broad. Mesopleuron and sections of lateral surfaces of propodeum with fine puncturation; dorsal surface of propodeum with transverse rugae.