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Sphaerechinus granularis is a species of sea urchin in the family Toxopneustidae, commonly known as the violet sea urchin. Its range includes the Mediterranean Sea and the eastern Atlantic Ocean, from the Channel Islands south to Cape Verde and the Gulf of Guinea. It favours sheltered locations and lives on rocks covered with seaweed or gravelly substrates. It is usually found in the neritic zone down to about thirty metres (100 ft) but occasionally down to a hundred metres (330 ft) in more exposed locations. It is also found in meadows of the seagrass Posidonia oceanica. It grazes on algae, especially encrusting coralline algae, seagrass blades and their epiphytic organisms and detritus. This S. granularis sea urchin was photographed off the coast of Madeira.Photograph credit: Diego Delso