Noble pen shell

Description:

It is a large species of clam, a marine bivalve mollusc in the family Pinnidae. It reaches up to 120 cm of shell length. This specimen was about 50 cm in lenght. It attaches itself to rocks using a strong byssus composed of many silk-like threads. The inside of the shell is lined with mother-of-pearl.

Habitat:

This species is endemic to the Mediterranean Sea, where it lives offshore at depths to 60 m. The noble pen shell has been listed as an endangered species in the Mediterranean Sea.

Notes:

Like all pen shells, it is relatively fragile to pollution and shell damage. There is a symbiotic relation between the Pinna Nobilis and a little crayfish often found living inside the shell. The little crayfish pinches the mussel when spotting danger. When pinched the mussel closes its shell. The crayfish is 3–7 cm long and totally transparent.