Updated: Jul 28, 2021
The Toxopneustes pileolus, more commonly known as flower sea urchin, flower tip urchin, sea hedgehog, or toxic sea urchin, looks like a beautiful sea bouquet. But don’t harvest these creatures, they may look harmless but these are the world’s most toxic urchins and can be deadly!
Appearance & anatomy
Flower urchins are relatively large sea urchins. They can reach a maximum diameter of 15 to 20cm (6 to 8 inches). The body of an adult is equally divided into identical segments around a central point in multiples of five. Each segment is ornamented by a large purple zigzag pattern running along its length.
The mouth is centrally located on the bottom surface. It is surrounded by a ring of small plates and five calcareous "teeth". The anus is on the upper surface and as the mouth, it is surrounded by a ring of small plates.
The spines are short and are usually hidden below the flower. They can vary from white, pink, yellow, light green, or purple in coloration with lighter-colored tips. The body is covered in flowers similar to white or pink-colored petals. The stings of the flower urchin are not from the spines, but rather from the petal-like triangular-shaped arms features that can be seen in the image below.
The triangular-shaped appendages have claws in them which can inject a mix of toxic chemicals into one.
Flower urchins are found across the tropical areas of the Indo-West Pacific. North from Okinawa, Japan to Tasmania, Australia in the south; and west from the Red Sea and the East African coast to Raratonga in the Cook Islands in the east. They frequent the coral reefs, coral rubble, rocks, sand, and seagrass beds at depths of 0 to 90m (0-295 ft) where there is abundant algae growth. Flower urchins can be found solitary or in groups, and often covered in detritus.
Poison & Sting
Countless people get injured by sea urchins every year. Most of the time it is a minor incident and all that is required is the first aid to remove a few spines from the victim’s skin accompanied by little pain.
Sea Urchins are highly venomous and can pierce through a wet suit. The poison itself is not necessarily fatal but the pain and shock of being stung may cause drowning.
If stung while scuba diving, get to the surface as soon and safely as possible. Once the effects of the poison kick in this may not be easy. The poisoned limb should be immersed in hot water. The poison is protein-based and the heat from the water will break up the protein chains. And of course, get to a doctor as soon as possible!
Their diet is short and simple. It consists of algae, bryozoans, and organic detritus.