BLENNIIDAE Meiacanthus urostigma, 3.4 cm SL (photo by Ukkrit Satapoomin) Meiacanthus urostigma Smith-Vaniz, Satapoomin and Allen, 2001 Tail-spotted Fangblenny D IV-V, 22-24; A II, 15-17; P1 28-30. Body slender, head strongly convex. Mouth small, subterminal; incisor teeth in jaws; a pair of canines posteriorly in each jaw; dentary glands positioned ventrally and encapsulated in dentary bone. No lateral line; mandibular pores 2; posttemporal pores 2; median supratemporal pores 2. Upper and lower lobes of caudal fin greatly produced in males. Color: light gray over most of head and body, grading to white on abdominal region; prominent mid-lateral black stripe extending from snout to caudal peduncle where it either terminates or connects to horizontally elongate black spot surround by yelloworange coloration that covers entire caudal peduncle; dorsal and anal fins dusky gray (translucent in females) with narrow white margin (and thin submarginal black stripe or line, which is prominent in females), frequently with narrow black stripe along base. Size: maximum length about 5 cm. Distribution: restricted distribution, presently known only from the Andaman Sea, from west coast of Thailand to Aceh, Weh Island, northern Sumatra. Remarks: inhabits shallow protected reefs and frequently forms small to large aggregations while hovering well above the bottom to feed on zooplankton. Youngs or juveniles are social mimics together with the juveniles of cardinalfish Cheilodipterus quinquelineatus. (Ukkrit Satapoomin)