Squared Biscuit Sea Star, from Ammouliani Island

Marine life|Biscuit sea star from Ammouliani|Chalkidiki|Greece

Peltaster placenta (Müller & Troschel, 1842)

Marine scientists have undertaken the difficult task of replacing the beloved starfish’s common name with sea star because, the starfish is not a fish. It’s an echinoderm, closely related to sea urchins and sand dollars. Starfish is the common name for a group of animals called sea stars. Sea stars are actually part of the phylum echinoderm and are related to sea urchins, brittle stars and sea cucumbers – they are not fish at all! Sea stars play an important role in deep-sea ecosystems, especially as predators of sponges and corals.

References: National Geographic

There are some 2,000 species of sea star living in all the world’s oceans, from tropical habitats to the cold seafloor. Biscuit Sea Stars are usually middle-sized sea stars with a characteristic double range of marginal plates bordering the disk and arms. Most of them have five arms, often short and triangular, around a broad central disc. Many species are pentagonal or subpentagonal, covered densely with granular, seed-like protuberances, hence the name of the family "seed-star" (gonium+aster). This distinctive bright orange-red sea star is called the Biscuit Sea Star because it is about the size of a large biscuit.

The upper surface of the Biscuit Sea Star is covered with many interlocking small plates and six to eight larger plates along the edge of each of their short arms.The Biscuit Sea Star lives on intertidal rocky shores and in coastal waters to a depth of 40 m, feed on sea squirts, sponges, bryzoans and algae.