Body elliptical and compressed, covered with imbricate plate-like scales. First dorsal fin over gill opening, with trigger-like locking structure. Posterior end of pelvis with movable encasing scales. A groove in front of eye. Enlarged osseous scales behind gill opening. Scales on side of body with no tubercles or spines, rather smooth. Upper jaw with two rows of teeth, the outer series with 8 teeth, the inner with 6. Lower jaw with 8 teeth arranged in a single row. Caudal peduncle compressed. Upper and lower lobes of caudal fin produced posteriorly. Anterior rays of soft dorsal and anal fins elevated, but not produced into filaments. Body dark brown dorsally, becoming white ventrally; all fins dark brown.
Distribution:
From Nova Scotia to Argentina.
Remarks:
This species is distinguishable from B. vetula by no blue lines on the head and the fewer numbers of soft dorsal and anal fin rays. (Matsuura)