Atlantic Purple Sea Urchin

Overview

The Atlantic Purple Sea Urchin (Paracentrotus lividus) is a well-known echinoderm found throughout the Mediterranean Sea and the eastern Atlantic Ocean. It is highly regarded in scientific research as a model organism for developmental biology and is also valued as a culinary delicacy in many coastal regions.

Appearance

This species features a circular, flattened test that is typically greenish in color. It is covered in long, sharp, and sturdy spines, which are most commonly purple but can also appear in shades of dark brown, light brown, or olive green. The tube feet are arranged in distinct arcs of five or six, corresponding to the pore pairs on its ambulacral plates.

Distribution & habitat

These urchins are commonly found in rocky intertidal zones, where they often inhabit self-excavated crevices or small depressions in the rock. They also frequent seagrass meadows, such as Posidonia oceanica, where they find both shelter and a reliable food source. Their presence is widespread across their range, often occurring in high densities on hard substrates.

Biology & behavior

Paracentrotus lividus is an opportunistic generalist that plays a significant ecological role by grazing on algae and seagrass, helping to regulate the structure of sublittoral communities. They are known for their ability to modify their environment, sometimes using their specialized teeth to bore into stone to create protective niches. While they are resilient, populations can be affected by seasonal diseases, such as the "bald disease," which causes spine loss and tissue lesions.