sentences:  "B. ambusticauda" can be differentiated from "B. melanopterus" by a shorter snout.Also, in "B. ambusticauda" the rictus (junction of the premaxilla and maxilla at the corner of the mouth) has posteriorly direct grooves that are curved instead of straight.Finally, "B. ambusticauda" has narrower black margins on the pelvic and anal fins (on the distal third or less instead of the distal half or more in "B. melanopterus").