The Psammechinus miliaris, or green sea urchin, is a small, spiny echinoderm found in shallow coastal waters across the North Atlantic and the Mediterranean. These creatures live on rocky seabeds, where they feed on algae, seaweed, and detritus, playing an essential role in maintaining the health of marine ecosystems.
In the water, sea urchins are slow-moving but highly effective at grazing. Their spines protect them from predators such as sea otters and starfish. Psammechinus miliaris is particularly valuable in studying ocean health, as its presence often indicates a stable ecosystem. However, overharvesting and habitat destruction pose threats to these vital marine organisms.