Pillow Cushion Star

A mature C. novaeguineae is pentagonal to subglobose in shape with an inflated appearance and much-abbreviated arms. It can grow to a diameter of 30 cm (12 in). Rows of tube feet are on the underside, and it has a central mouth. The colour is very variable and includes a mottling with darker and lighter shades of fawn, brown, orange, yellow and green. The armoured body wall is made of calcareous ossicles which are supported internally by pillars which buttress the ambulacra. The armouring contains pits into which the tube feet can be retracted. The body cavity is filled with water. On the dorsal face, they can be covered with small conical tubercles, as well inside as outside of papular areas.

Culcita novaeguineae is found in the Indian and Pacific Oceans. Its range extends from Madagascar and the Seychelles to the Philippines, New Guinea (for which it is named), Australia and Hawaii.

A number of organisms live in or on C. novaeguineae. The small shrimp Periclimenes soror lives as a commensal hiding under the cushion star. Astroxynus culcitae, Stellicola oreastriphilus and Stellicola parvulipes are copepods which live parasitically on the outside of the cushion star. The star pearlfish (Carapus mourlani) sometimes lives as a commensal inside the cushion star, working its way into the large body cavity through an ambulacral groove and emerging periodically to feed.