Sundadanio margarition Conway, Kottelat & Tan 2011

Distinguished from all congeners by the following combination of characters: large adult size (largest specimen examined 19.7 mm SL); live males with emerald blue-green sheen present across dorsal body surface and an intense black-red marking across anterior portion of anal fin; preserved males with a well developed dark lateral stripe of roughly uniform depth along entire length, horizontal through ventral border of which, when brought forward, extendingthrough dorsal half of eye; presence of a weak secondary lateral stripe of small melanophoresrunning parallel to dark lateral stripe along its ventral margin from posterior to opercularopening to point opposite middle of anal fin; secondary lateral stripe of males not visible inlive specimens; absence of reticulate pattern over dorsal body surface; absence of dusky markings on distal tips of dorsal and caudal fins; presence of enlarged scales next to window in body musculature; scales posterior to enlarged scales next to window in body musculature and anterior to anal-fin origin with a single small tubercle at center; complete covering of scales on caudal peduncle (Ref. 88800).Description: Dorsal-fin rays ii.6.i; anal-fin rays iii.6; pectoral-fin rays i.6-7.i-ii; pelvic-fin rays i.5.i (Ref. 88800).

Dorsal soft rays (total): 9; Analsoft rays: 9; Vertebrae: 34

Inhabits swamp forests and blackwater streams (Ref. 88800).