Black Longspine Urchin

Overview

The Black Longspine Urchin is a highly recognizable echinoderm known for its exceptionally long, slender spines and distinctive coloration. It is a widespread species across the tropical Indo-Pacific and has recently expanded its range into the Eastern Mediterranean Sea.

Appearance

This urchin features a near-spherical, black test that can reach approximately 9 cm in diameter. Its most defining characteristic is a bright orange ring surrounding the anal papilla on the upper surface of the body. The test also typically displays five white or blue spots. The primary spines are extremely long, often exceeding 30 cm, and are thin and brittle. While generally black, these spines can sometimes appear white, grey, or mauve, and juveniles may exhibit banded patterns.

Biology & behavior

Primarily nocturnal, these urchins spend the daylight hours hiding in crevices or under reef overhangs to avoid predators. They emerge under low-light conditions to forage. While they possess mildly venomous spines that can cause painful stings if touched, they are not considered a serious threat to humans. Despite their formidable defenses, they are occasionally preyed upon by specialized feeders such as triggerfish and pufferfish.

Feeding

As a dominant grazer, this species plays a vital role in maintaining coral reef health by feeding on algae. It is an opportunistic omnivore, scraping algae from rocky substrates and coral surfaces, which helps prevent algal overgrowth in its habitat.

Distribution & habitat

Native to the Indo-Pacific, this species is found from Africa and the Red Sea to Australia and Japan. It inhabits a variety of environments, including coral reefs, rocky reef platforms, lagoons, and seagrass beds. It has also successfully established populations in the Eastern Mediterranean following migration through the Suez Canal.