Diplodus prayensis was first formally described in 1964 by the French ichthyologist Jean Cadenat with its type locality given as the port of Praia on Santiago in Cape Verde.

[6] Diplodus prayensis has an oval shaped, compressed body with a slightly protrusible mouth which has moderately fleshy lips.

The overall colour is brownish to greenish with alternating gold and grey horizontal lines along the scale rows.

There is a dark bar on the caudal peduncle which is more extensive in adults, reaching the base of the rearmost rays of the dorsal and anal fins.

[2] Diplodus prayensis is found in the eastern Atlantic Ocean where it is endemic to the Cape Verde Islands.