The Mediterranean star red, (Echinaster sepositus), is a species of starfish from the East Atlantic, including the Mediterranean Sea. stella marina rossa Echinaster sepositus echinoderma intotheblue.it
Echinaster sepositus has five relatively slender arms around a small central disc. It usually has a diameter of up to 20 cm, but can exceptionally reach up to 30 cm. It is of bright orange-red in colour. The surface is dotted with evenly spaced pits from which the animal can extend its deep red gills (papullae).
Common throughout the Mediterranean Sea up to 200 meters deep, it can be found both along the surface of rocks and between Posidonia beds, but not at temperatures above 22 ° C. stella marina rossa Echinaster sepositus echinoderma intotheblue.it
Echinoderms possess a unique water vascular system. This is a network of fluid-filled canals derived from the coelom (body cavity) that function in gas exchange, feeding, sensory reception and locomotion. This system varies between different classes of echinoderm but typically opens to the exterior through a sieve-like madreporite on the aboral (upper) surface of the animal. The madreporite is linked to a slender duct, the stone canal, which extends to a ring canal that encircles the mouth or oesophagus. From this, radial canals extend along the arms of asteroids and adjoin the test in the ambulacral areas of echinoids. Short lateral canals branch off the radial canals, each one ending in an ampulla. Part of the ampulla can protrude through a pore (or a pair of pores in sea urchins) to the exterior and is known as a podium or tube feet. The water vascular system assists with the distribution of nutrients throughout the animal’s body and is most obviously expressed in the tube feet which can be extended or contracted by the redistribution of fluid between the foot and the internal sac.