A brown feather starfish coiled up tightly
Feather stars also known as crinoids. They are characterized by radial symmetry. The body of a typical feather star is cup-shaped, their numerous feathery arms project from a central disc. Some have five arms, others as many as 200. The arms, called pinnules are coated with a sticky substance that helps to catch food. There are appendages known as cirri attached to the underside of the body with which they cling to to sponges or corals. Both their mouth and their anus are situated on the upper side.
Ecology and range of feather stars
Feather stars are primarily nocturnal but they are seen in the open during the day with their arms rolled up.
Behavior of feather stars
Feather stars can crawl, roll, walk and even swim but usually they cling to sponges or corals. Feather stars are very abundant in areas exposed to periodic strong currents, because they feed on plaktonic food.
Numerous animals live in close association with feather stars. Echinoderms are hosts to various symbiotic animals such as the crinoid clingfish (Discotrema crinophila), the elegant squat lobster (Allogalathea elegans) or the crinoid shrimp (Periclimenes sp.). These animals receive shelter and food (left over) and also feed on microorganisms living on feather stars.