This species is distinguished from R. stewari by the following characters: snout shape is wider and more projected with snout length 14.6-15.1% SL (vs. 11.3-13.3% SL); with shorter caudal peduncle, its postanal length 45.2-46.1% SL (vs. 48.9-50.8% SL); the dorsal-fin is closer to caudal-fin, its postdorsal length 54.3% SL (vs. 57.5-59.0% SL); abdomen totally covered with plates, loosely connected in examined specimen (vs. abdomen partially or totally covered with plate) (Ref. 124527).