A new species of the rare ant genus Metapone – Metapone murphyi – is described based on aged museum material: a single nest series (workers, queens and males) collected from a decayed coconut (tree) stump on Pulau Sakra – previously an offshore island south of mainland Singapore.  Workers can be distinguished from other named congeners mainly by the following characters: 1) subpetiolar lamella subrectangular; 2) short subpetiolar edge and roundly obtuse subpetiolar angle; 3) outer margin of posterior subpetiolar face forming a continuous, U-shaped, translucent, laminate carina; 4) subtrapezoidal petiole in dorsal view with extended blunt tooth-like posterolateral corners. Detailed description and illustrations of the male genitalia are given for the first time in the genus. The key to Asian species of Metapone is updated to include the new species.