In 1975, Fell re-examined the genus but was unable to find sufficient differences to justify separating them into two species.

There are a number of club-shaped spines on the oral (lower) surface, a characteristic that this species shares with C. besnardi and C. coronatus but not other members of the genus.

The subspecies C. l. longispinus has spines banded in purple on a pale green, buff or whitish background.

It forms part of a species-rich community which includes other sea urchins, mollusks, polychaete worms, crabs and encrusting organisms.

[2] Examination of the contents of this urchin's stomach have shown that C. longispinus largely feeds on several species of red algae.