GOBIIDAE Oplopomus oplopomus, 5.0 cm SL (photo by Ukkrit Satapoomin) Oplopomus oplopomus (Valenciennes, 1837) Spinecheek Goby D VI+I, 10; A I, 10; P1 17-19; LR 28-30; PDS 0-5. Body moderately elongate, compressed. Head subcylindrical; lower jaw slightly projecting beyond upper jaw; 1-2 distinct spinous projections at posterior margin of preopercle; gill opening just or not extending anteriorly to a vertical through preopercular margin; tongue near truncate. Anteriormost spines of dorsal fins pungent, non-flexible; pelvic fins united medially; frenum present. Scales on body ctenoid, except for mid-anterior part of nape, breast and pectoral-fin base with cycloid scales; head naked. Sensory canals and pores present on head; multiple longitudinal rows of sensory-papillae on cheek; aggregation of sensory papillae just behind chin. Color: ground color of head and body pale gray; a midlateral series of 5 black spots on body, in addition to a several smaller black spots on dorsal half of body; several irregular-shaped sky spots on head; numerous sky and orange yellow spots scattered on body. Size: 7.0 cm SL. Distribution: Indo-West Pacific. Remarks: found on muddy or sandy-mud bottoms in protected bays.