Body (test) to 10cm
Dense covering of short spines arranged in rows or clusters. Body white to gpale greenish, spines white, red, purple or blue. Obvious white, bubble-like pedicellariae between spines. Often covered in organic debris held in place with tube feet.
Sand and seagrass beds to 150ft (5m). Its Aristotle's organ around the mouth has five teeth that can be used to rasp surfaces. It is largely herbivorous, feeding on the seagrass Thalassia. Its tube feet and spines also play a role in feeding, catching and holding bits of debris that float past.
It is sometimes found in aggregations of closely packed individuals, which might be linked to breeding.
It is thought that the urchin is photo-sensitive and that pieces of debris may provide some protection from strong sunlight and ultraviolet light in the clear shallow waters it favours.
Eggs and sperm are liberated into the water column and fertilisation is external. The larvae are planktonic and are known as pluteus larvae. They pass through several developmental stages before undergoing metamorphosis into juvenile urchins.
| Ecological Descriptors
Green Sea Urchin