Diadema mexicanum is a species of long-spined sea urchin belonging to the family Diadematidae.

[1] It is native to the Pacific coast of Mexico, Costa Rica, El Salvador, Nicaragua and Panama.

The coral reefs off the Pacific coast of Central America are thin and small relative to their counterparts in the Indo-Pacific and Caribbean.

[2] Diadema mexicanum is a herbivore and an important member of the reef community and plays a significant role in controlling algal growth.

However, when the populations of sea urchins get too large their spines cause excessive abrasion to the corals and bioerosion of the reef.