The mouth is inferior and is overhung by the snout. A fleshy upper lip covers a small cartilaginous plate in the upper jaw. The lower lip, however, is covered by a hard cartilaginous sheath that has a virtually straight-cutting edge. This chisel-like mouth is where the chiselmouth gets its name. This hard sheath, however, is absent in juvenile chiselmouth.
Pharyngeal teeth are stout and hooked.
The dorsal fin on A.alutaceus begins behind the origin of the pelvic fin, and generally has ten fin rays. The caudal fin is distinctly forked, and the anal fin's origin is behind the termination of the dorsal fin. The number of fin rays is usually nine, and occasionally ten. Pelvic fins are well developed, and rather narrow, with nine to ten fin rays. The peritoneum in intensely black and the intestine is at least twice the body length.