Noble Pen Shell

Noble pen shell, Pinna nobilis, also known as the fan mussel, is a large clam of the family Pinnidae, the pen shells, endemic to the Mediterranean Sea. It is among the largest bivalve mollusks in the world, its tall, wedge-shaped shell anchoring upright in seagrass beds and soft sediment by a bundle of fine threads called byssus, historically collected and woven by hand into a rare fabric known as sea silk.