What is Pinna nobilis?

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What is Pinna nobilis? Blog Image


Recently, marine biologists said that a huge clam that was on the verge of extinction has made a comeback, with a surge in numbers in waters off Croatia.

About Pinna nobilis

  • It is a large species of Mediterranean clam, a marine bivalve mollusc in the family Pinnidae.
  • The clams, whose shells can grow as much as 1.2 m across, play an important ecological role by filtering sea water and allowing other organisms to flourish.
  • It attaches itself to rocks using a strong byssus composed of many silk-like threads which used to be made into cloth.
  • The animal secretes these fibres from its byssus gland; they consist of keratin and other proteins and may be as long as 6 cm (2.4 in). The inside of the shell is lined with brilliant mother-of-pearl.
  • As with other members of its genus, Pinna nobilis hosts symbiotic shrimp which live inside its shell.
  • It is believed that when it sees a threat, the shrimp warns the host, perhaps by retracting its claws or even by pinching. The clam then closes shut.
  • It has been demonstrated that the shrimp has a similar filter-feeding diet to its host and the relationship is likely mutualistic.
  • Distribution: This species is endemic to the Mediterranean Sea. 
  • Threats: It is relatively fragile to pollution and shell damage.
  • The clam, known as the noble pen shell or pinna nobilis, started dying out as a deadly pathogen spread in parts of the Mediterranean around 2016.
  • Conservation status
    • IUCN: Critically endangered

Q1) What are Mollusks?

These are any soft-bodied invertebrate of the phylum Mollusca, usually wholly or partly enclosed in a calcium carbonate shell secreted by a soft mantle covering the body. Along with the insects and vertebrates, it is one of the most diverse groups in the animal kingdom.

Source: Pinna nobilis: Comeback hero