Distinguished by the following characteristics: lacking scales on side of head, predorsal midline and pectoral fin base, no distinct flap on end of lower lip (low fold may be present), and no distinct canine or enlarged teeth; sexually dimorphic in adult size and colour, with females averaging larger than males; sexually dichromatic: males with row of six dusky to blackish spots or blotches along mid-side of body, posteriormost 3-4 blackish spots darker and larger than anterior spots and surrounded by small iridescent blue spots in life, small dense black spots scattered on unpaired fins; females with broken grey line along midside of body and dusky to blackish spots or blotches indistinct and posterior blotches not darker than anterior ones, no small iridescent blue spots on body; second dorsal fin rays modally I,10; anal fin rays modally I,11; pectoral rays 15-18; lateral scales 24-28; predorsal scales absent from nape midline, scales on side of head may reach from just over opercle to nearly behind eyes (Ref. 92171).