Violet Sea Urchin

Overview

The Violet Sea Urchin (Sphaerechinus granularis) is a robust, regular sea urchin easily recognized by its thick, blunt spines and somewhat flattened, purple-colored test. It is the only species within its genus and is commonly found across the Mediterranean Sea and the eastern Atlantic Ocean.

Appearance

This species typically reaches up to 15 cm in diameter. Its spines are short, uniform in length, and arranged in neat rows. There are two primary color variations: one with a purple test and purple spines, and another with a purple test and white-tipped or entirely white spines. The spines are notably blunt, making them less sharp than those of many other urchin species.

Distribution & habitat

Sphaerechinus granularis inhabits a variety of environments, including rocky reefs, gravel beds, and seagrass meadows. While it can be found in the intertidal zone, it is frequently observed in deeper sublittoral waters, ranging down to approximately 130 meters.

Biology & behavior

This urchin is a common grazer that feeds primarily on algae, including encrusting coralline algae, as well as seagrass and detritus. It is well-known for its "covering" behavior, where it uses its tube feet and specialized claw-like structures called pedicellariae to hold fragments of shells, pebbles, or algae over its body for camouflage. Spawning typically peaks in spring and early summer, releasing eggs and sperm into the water column to produce planktonic larvae.