Echinoderms

sea urchin

Parcours précédent parcours suivant

Identity card

sea urchin

Scientific name:: Diadema setosum

Family:: Diadematidae

Class:: Echinoidea

Phylum:: Echinodermata

Year of description:: Leske, 1778

IUCN Status:: Not Evaluated

CITES-status:: Not Evaluated

Distribution:: Red Sea, Indian Ocean, Pacific Ocean as far as Polynesia and from southern Japan to Australia

Habitat:: It lives at shallow depths in lagoons.

Size:: It measures about 10 cm including its legs and has a shell measuring 3 cm. It looks similar to a spider.

Diet:: Encrusting algae and organic matter.

To defend themselves against predators, such as titan triggerfish, sea urchins form large groups.

The sea urchin provides shelter for many animals such as gobies, cardinalfish, shrimps and even some jellyfish. The Banggai cardinalfish also hides in its spines to protect itself from potential predators.

did you know?

Biomimicry: the sea urchin's mouth and teeth have been used as a model for a grabber capable of sampling sediments on other planets such as Mars.

Where is the animal to be found?

It is found in the Red Sea, the Indian Ocean, Reunion and Mayotte, Madagascar, the Mascarene Basin, the Pacific Ocean as far as Polynesia and from southern Japan to Australia and New Caledonia. It is now found in the eastern Mediterranean, probably as a result of its larva being transported through the Suez Canal.

It lives in lagoons, on the surface of rocks, and on the sand near coral reefs, usually at a shallow depths. It is also found in seagrass beds and in disrupted environments where dead corals are abundant.

How can it be recognised?

Males and females cannot be identified morphologically. It looks similar to a spider.

What is distinctive about it?

Sea urchins breed by external reproduction, usually when the water temperature exceeds 24°C. The larvae drift for several months before sinking to the seabed to metamorphose into young urchins.