POLYNEMIDAE Eleutheronema tridactylum, 17.5 cm SL (preserved specimen; photo by Mark Sabaj) Eleutheronema tridactylum (Bleeker, 1845) Threefinger Threadfin D VIII+I, 13-14, 9; A III, 14-15; P1 16-18+3 filaments; P2 I, 5; LLp 72-79; GR 4-10. Body elongate, moderately compressed. Posterior margin of maxilla extending well beyond a vertical through posterior margin of adipose eyelid. Upper jaw length 6.3-7.1 in SL. Anterior parts of lower jaw with small teeth extending onto lateral surface, adjacent portion of lip absent; tooth plate extension onto lateral surface of lower jaw 10.0-11.1 in SL; vomer lacking deciduous tooth plates on both sides throughout life. Longest pectoral filament not reaching origin of anal fin. Swimbladder absent. Color: upper sides of head and trunk with green, becoming silvery-white or yellowishwhite on lower sides; dorsal, pectoral, and caudal fins dark with black borders. Size: maximum length 25 cm SL. Distribution: known only from Thailand, Malaysia and Indonesia. Remarks: probably occurs on muddy and sandy substrata.