Echinoderms
Identity card
Tropical Indo-Pacific: from East Africa to Hawaii and the Galápagos Islands, as far as Japan and Australia. Observed in Réunion, Mayotte, Polynesia and New Caledonia.
Lagoons, seagrass beds, algae-rich flats, reefs, sandy and muddy bottoms. Abundant up to 15 m.
Maximum diameter of 16 cm.
Herbivore that feeds on seaweed.
The name "priest's cap" in French is linked to the appearance of its skeleton.
Its calcareous skeleton, called a test, is spherical in shape and flattened on the top and bottom. It resembles the hats once worn by Catholic priests.
It is called a "collector urchin" in English to illustrate its collector behaviour because it uses its podia (small sucker feet) to hold pieces of seaweed, shell fragments or pebbles on its skeleton. This acts as camouflage against predators (such as triggerfish) and protection against UV rays in very shallow waters.
Mankind and shores
The Ocean Mag
In the spotlight
Nausicaá est présent à Erevan pour suivre les discussions de la COP17 et contribuer à faire entendre les enjeux liés aux écosystèmes marins.
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La 17e Conférence des Parties pour la biodiversité se déroule du 19 au 30 octobre 2026 en Arménie.
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A new El Niño event, described as “very strong”, is set to occur from this spring onwards.