Syncomistes bonapartensis is distinguished from all congeners within the Syncomistes complex by a combination of the following characters: both adults and juveniles with lower jaw rounded anteriorly making a ‘U-shape’ when viewed from below; mouth slightly oblique; teeth broad and large relative to Syncomistes, flat, asymmetric, margins convex posteriorly and straight to slightly concave anteriorly, widest point closest to midpoint of tooth, apical region tapered to slight point; usually with 7-8 slightly wavy brown stripes running horizontally along body sides; usually with < 11 gill rakers on the upper arch and < 30 in total; and usually with ? 6.0 teeth per mm of jaw (Ref. 119336).