Sea stars belong to the Echinodermata phylum, which also includes sea urchins, sea cucumbers and brittle stars. The spiny starfish is unmistakeable - firstly, it is HUGE, growing to the size of a dustbin lid. Secondly, it really is very spiny - its whole body covered in white spines. It lives in shallow waters close to shore and down to depths of 200m. Spiny starfish are pale and normally pretty easy to spot on the seabed. Their skin is a pale grey-green and they often have beautiful purple tips to the end of their arms. Like other starfish, they too are a voracious predator and prey on bivalve molluscs, crustaceans and other starfish.The spiny sea star can be found in a variety of habitats, from sheltered muddy areas to wave-exposed rock facades,  and at depths that range from extremely shallow down to about 200 m.Did you know?When disturbed or stressed, this species will often shed one or more of its legs. Don't worry they will grow back! Spiny starfish are often spotted with 3 or 4 normal legs and 1 or 2 small legs in the process of regrowing.