This species differs from T. heteromorpha in the following characters: a gently sloping lateral head profile to pre-dorsal region (vs. steep convex); sub-superior mouth (vs. terminal); caudal apex of axine not reaching caudal-fin base (vs. reaching and extending to hypural plate); dorsal and ventral apices of axine originate posterior to both dorsal-fin and pelvic-fin origins by up to three scale-widths (vs. dorsal apex starting one scale-width posterior to dorsal-fin origin and ventral apex starting at pelvic-fin origin); faint or indistinct brown humeral streak just posterior to opercular opening (vs. a distinct black humeral streak); base of dorsal fin hyaline and its middle reddish-orange in life (vs. anterior two-thirds orange-red); a distinct orange-red colour on anal fin in life (vs. faint or absence); body in life with a bluish-lilac sheen (vs. reddish or purplish sheen); a shallower body (depth at dorsal-fin origin 28.3-34.6% SL [mean 32.4], vs. 32.6-38.2% [mean 35.8]) (Ref. 122370).