Trigonostigma Truncata, A New Species Of Harlequin Rasbora From Malay Peninsula (Teleostei: Danionidae)

Trigonostigma truncata, new species, is described from the coastal swamp forests along the east coast of the Malay Peninsula. It differs from all congeners, in having a gently sloping lateral head and nape shape, the characteristic black triangular marking, newly termed here as the axine, which is large with its caudal apex not reaching caudal-fin base, presence of orange-red colour on the anal fin, a bluish-lilac coloured sheen on body in life, and a shallower body depth as compared to its most similar congener, T. heteromorpha. A key to the genus Trigonostigma and a brief redescription of T. heteromorpha is also included.