Pinna nobilis

Pinna nobilis
Live specimen of Pinna nobilis, in Levanto, Liguria (Italy)
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Pterioida
Family: Pinnidae
Genus: Pinna
Species: P. nobilis
Binomial name
Pinna nobilis
Linnaeus, 1758
Synonyms

Pinna gigas Chemnitz

Pinna nobilis, common name the noble pen shell or fan mussel, is a large species of Mediterranean clam, a marine bivalve mollusc in the family Pinnidae, the pen shells. It reaches up to 120 cm (4 ft) of shell length.[1]

Description

Live specimen of Pinna nobilis, in Levanto, Liguria

The bivalve shell is usually 30–50 cm (1.0–1.6 ft) long,[2] but can reach 120 cm (4 ft).[1] Its shape differs depending on the region it inhabits. Like all pen shells, it is relatively fragile to pollution and shell damage. It attaches itself to rocks using a strong byssus composed of many silk-like threads which used to be made into cloth. These keratin fibres that the animal secretes by its byssus gland are even 6 cm (2.4 in) long. The inside of the shell is lined with brilliant mother-of-pearl.[3]

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 3-7cm long and totally transparent.

Distribution

This species is endemic to the Mediterranean Sea, where it lives offshore at depths ranging between 0.5 and 60 m (1.6 and 196.9 ft).[4] It could be found buried beneath soft-sediment areas (fine sand, mud, often anoxic).[5]

Human relevance

This species is the origin of sea silk, which was made from the byssus of the animal.[6]

In recent years, Pinna nobilis has become threatened with extinction, due in part to fishing, incidental killing by trawling and anchoring, and the decline in seagrass fields; pollution kills eggs, larvae, and adult mussels.[6] The noble pen shell has been listed as an endangered species in the Mediterranean Sea. The European Council Habitats Directive 92/43/EEC, on conservation of natural habitats and the wild fauna and flora, proclaims that P. nobilis is strictly protected (by the Annex IV of EEC, 1992)- all forms of deliberate capture or killing of fan mussel specimens are prohibited by law.[5]

As part of the Costa Concordia disaster recovery effort going on in Italy (2012), a group of about 200 Pinna nobilis was manually relocated to a nearby area due to the threat posed by subsequent engineering work.[7]

References

  1. 1 2 Zavodnik, D., Hrs-Brenko, M., & Legac, M. (1991). Synopsis of the fan shell P. nobilis L. in the eastern Adriatic sea. In the C. F. Boudouresque, M. Avon, & V. Gravez (Eds.), Les Especes Marines a Proteger en Mediterranee (pp. 169–178). Marseille, France: GIS Posidonie publ.
  2. Acquario di Genova (2006). Pinna nobilis. Retrieved 15 September 2014.
  3. Tyndale (1849): The Island of Sardinia, including Pictures of the Manners and Customs of the Sardinians, . . . Three Volumes. John Warre Tyndale. London: Richard Bentley. pp. 77–79.
  4. Butler, A., Vicente, N., De Gaulejac, B. (1993). Ecology of the pteroid bivalves P. nobilis bicolor Gmelin and P. nobilis L. Marine Life, 3(1-2), 37-45.
  5. 1 2 Centoducati, G., Tarsitano, E., Bottalico, A., Marvulli, M., Lai, O., Crescenzo, G. (2006). Monitoring of the Endangered Pinna nobilis Linee, 1758 in the Mar Grande of Taranto (Ionian Sea, Italy). In the Environ Monit Assess (2007) 131:339-347.
  6. 1 2 Hill, John E. (2009) Through the Jade Gate to Rome: A Study of the Silk Routes during the Later Han Dynasty, 1st to 2nd centuries CE. John E. Hill. BookSurge, Charleston, South Carolina. ISBN 978-1-4392-2134-1. See Section 12 plus "Appendix B – Sea Silk". pp. 468–476.
  7. Reuters video about the Pinna nobilis relocation

See also

Further reading

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