Also known as Imperial Lance Urchin, Imperial Urchin, Knobby Sputnik Sea Urchin, Lance Urchin, Land Mine Sea Urchin, Mine Urchin, Pencil Sea Urchin, Pencil Urchin, Sputnik Sea Urchin, Sputnik Sea Urchin Seashell, Sputnik Urchin.
Found singly hiding in holes and hollows during the day venturing out to feed at night over shallow reefs.
They feed on algae, small invertebrates and sponges.
Their spikes vary in colour.
Length - 10cm
Depth - 0-70m
Widespread Indo-West Pacific
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/Phyllacanthus_imperialis