Bunocephalus hartti is distinguished from other species of Bunocephalus by the absence of serrations along the anterior margin of the pectoral-fin spine in adults (vs. presence). It further differs from most congeners, except for B. verrucosus, by having the last dorsal-fin ray completely or almost completely adnate to the dorsum (vs. dorsal-fin ray completely free or with less than half extension connected to the dorsum) (Ref. 104710).