Appearance
The rock cale has an elongate body which has a depth equivalent to roughly a third to a quarter of its standard length. It has a short snout and a rounded head which has a small mouth which is slightly downturned and has fleshy lips, the upper lip projecting. The jaws have small, The jaws have small, tricuspid teeth with a few sharply pointed ones too and they are set on 3-4 rows in the jaws. The outermost row has the largest teeth and there are no vomerine teeth. There are two pairs of nostrils, the front pair have fleshy flap with small tentacles on the front and rear margins. There is a wide, flattened spine in the operculum which does not reach the margin. The dorsal fin has a long base but it is nearly split in two by a deep and wide incision between the spiny and soft rayed parts.
