Long-spined sea urchin
Diadema setosum
- Scientific name
- Diadema setosum
- Group
- Echinoderms (starfish, urchins...)
- Rarity
- Common
- Where to see it
- Indo-Pacific & Red Sea
- Conservation status (IUCN)
- Not evaluated
Did you know?
The long-spined sea urchin bristles with very long, hollow, mildly venomous spines that can break off in skin on contact and stay painfully lodged there. Though it has no eyes, its whole body is light-sensitive, allowing it to detect the shadow of an approaching predator.
What defines this group — Echinoderms (starfish, urchins...)
Starfish, urchins and sea cucumbers: a five-fold symmetry found nowhere else in the animal kingdom.
- The body is arranged in fives around a centre: no head, no front, no back.
- They move on hundreds of tube feet driven by water under pressure.
- Many regrow a lost arm; some starfish can rebuild themselves from a single one.