Pillow cushion star

Large and very common sea star, shape pentagonal, like inflated, with very short arms. Colour is extremely variable: beige, brown, red, yellow, green, with plates and tubercles often in contrasting colour compared with the background. 30 cm diameter.
It is very common in lagoon, back reef and reef front. It feeds on detritus and on sessile invertebrates, sometimes including hard corals (anyway it can not be considered a serious threat for the coral reefs). The pentagonal shape is distinctive toward the cushion star Choriaster granulatus. Culcita schmideliana is very similar, but it lives in the Indian Ocean. In our area an unidentified Culcita sp. exists, identified by shape and colour of the plates on the oral (lower) side.