GOBIIDAE Istigobius ornatus, 5.4 cm SL (photo by Ukkrit Satapoomin) Istigobius ornatus (Rüppell, 1830) Ornate Goby D VI + I, 10-11; A I, 8-10; P1 17-20; LR 27-28; PDS 9-12. Body moderately elongate and compressed. Head subcylindrical or slightly depressed; snout rounded, slightly projecting anteriorly beyond upper jaw; lower jaw not projecting beyond upper jaw; gill opening not extending anteriorly to a vertical through preopercular margin. Upper part of pectoral fin with some filamentous free rays; pelvic fins united medially; frenum present. Scales on head and body ctenoid, except for occipital region, breast and pectoral-fin base with cycloid scales; head naked. Sensory canals and pores present on head; longitudinal pattern of sensorypapillae rows on cheek; curved or near transverse sensory-papillae row just behind chin. Color: head and body pale gray, with numerous small black dots or horizontally-elongate blotches; distal tip of first dorsal fin tinged with yellow. Size: 10.0 cm SL. Distribution: eastern Indian Ocean, Andaman Sea and Indonesia. Remarks: found in mangrove areas and bays with sandy or muddy bottoms.