Also known as Black Urchin, Erizo Negro, Long-spined Sea Urchin, Mediterranean Sea Urchin.
Found singly or in large groups usually in shallow waters over rocky coastlines.
They feed on small filamentous algae and red algae.
Length - 10cm
Depth - 0-30m
Widespread Atlantic, Mediterranean
Sea Urchins use tubed feet to get around, often in large impenetrable masses for protection.
Sometimes they hitch a lift on the back of crabs.
They have well developed jaws for grinding their prey.
Their anus is on top in most sea urchins, except the heart urchins where it is at the rear.
Predators of sea urchins are triggerfish and large wrasses, who nibble away at their spines before turning them over to eat the fleshy undersides.
Sea Urchins are highly venomous and can piece through a wet-suit.
Some are sensitive to light and have the ability to shoot venom loaded spines at a short distance.
To be avoided!! Ref: https://en.wikipedia.org/wiki/Arbacia_lixula