Diagnosis: body with 3 broad, oblique, dark cross bars; numerous pale striae along sides, corresponding to the center of each longitudinal scale row; head and pectoral-fin bases with white spots and mottling; predorsal scales extend well anterior to level of preoperculum, and anterior margin of scaled area appears convex in dorsal view (Ref. 57403, 79590). 4-5 outer/upper pectoral-fin rays free (Ref. 57403, 79590), hence its name "Frillfin goby" (Ref. 26938). Body shape is terete, slightly depressed; eyes situated dorso-laterally; reduced swim bladders (Ref. 92840).

Description: predorsal scales extending anteriorly beyond level of preopercle, towards rear edge of orbit, with anterior margin of scaled area convex in dorsal view (Ref. 79590). 16-27 (usually 18-24) predorsal scales; 33-40 (usually 36 or 37) scales in a longitudinal series (including 3-5 scales on caudal fin base), 12-14 (usually 13) scales in rearward transverse series; 1st dorsal fin: VI; 2nd dorsal fin: I,8-9; anal fin I,7-9 (usually 8); pectoral fins: 18-21 (usually 19 or 20), 4-5 outer (dorsal) ones free; caudal fin: 14 or 15 branched rays (Ref. 57403, 79590).

Coloration: Preserved specimens: 3 broad, oblique cross bars on body, middle one often paler than others; flanks with numerous pale striae, corresponding to scale centers of each longitudinal scale row (less distinct in large individuals); head with dark mottling, including intense dark spot behind eye and a more diffuse spot above preoperculum; cheeks, operculum and pectoral-fin bases covered with pale spots; faint lateral pre- and suborbital bands present; distal area of 1st dorsal fin pale, middle part with a broad dark band; 2nd dorsal fin with dark, oblique bands, sometimes confluent, and more intense posteriorly; anal fin dark, in particular posteriorly; bases of pectoral fins with upper and lower areas dark; pelvic dark with a paler rim; caudal fin with 3-4 concentric dark bands (Ref. 57403, 79590). In life: margins of both dorsal fins pink; 1st ray of 2nd dorsal fin with 3 black spots; ventral rays of caudal fin olivaceous green; spots on body olivaceous to black (Ref. 57403, 79590).