Pinna nobilis | |
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Live specimen of Pinna nobilis, in Levanto, Liguria (Italy) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Bivalvia |
Order: | Pteriida |
Superfamily: | Pinnoidea |
Family: | Pinnidae |
Genus: | Pinna |
Species: | P. nobilis |
Binomial name | |
Pinna nobilis | |
Synonyms | |
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Pinna nobilis, known by the common names noble pen shell and fan mussel, is a large species of Mediterranean clam, a marine bivalve mollusc in the family Pinnidae, the pen shells. [2]
It reaches up to 120 cm (4 ft) of shell length. [3] It produces a rare manganese-containing porphyrin protein known as pinnaglobin. [4]
The bivalve shell is usually 30–50 cm (1.0–1.6 ft) long, [5] but can reach 120 cm (4 ft). [3] 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. 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. [6]
As with other members of its genus, Pinna nobilis hosts symbiotic crustaceans which live inside its shell; in this case it is the shrimp Pontonia pinnophylax and the pea crab Nepinnotheres pinnotheres . [7] 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. [8]
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). [9] It could be found buried beneath soft-sediment areas (fine sand, mud, often anoxic). [10]
This species is the origin of sea silk, which was made from the byssus of the animal. [11]
In 2016, an outbreak of one disease caused the mortality of 99% of its population in Spain. The cause of the disease was a newly discovered pathogen, Haplosporidium pinnae , which still poses a serious threat to the survival of the species. By 2019, mortality spots had been detected in Greece, Croatia, Turkey, Tunisia, France and Morocco. In the Trieste area, considerable efforts have also been made to conserve the deposits since 2020. [12] [13] In the past, Pinna nobilis faced 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. [11] Such threats, however, have been very localised and have not led to such a widespread and rapid population decline. The pathogen, which is still present in the environment, will make recovery a challenge, so continuing declines are expected. The percentage of population size reduction over the last ten years is over 80%. In December 2019, Pinna nobilis has entered the IUCN Red List as critically endangered. [14] [15]
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. [10]
As part of the Costa Concordia disaster recovery effort in Italy in 2012, a group of about 200 Pinna nobilis was relocated to a nearby area due to the threat posed by subsequent engineering work. [16]
The byssus of Atrina pectinata , a shell of the same family, has been used in Sardinia as a substitute for Pinna nobilis, to weave sea silk. [17]
Pinna nobilis is sensitive to exceptional pollution. Many die due to anchoring; additionally, illegal extraction, which has been prohibited in Croatia since 1977, is still present. It has been placed on the list of strictly protected species in Croatia. Any extraction of P. nobilis out of the sea is heavily fined.
Mussel is the common name used for members of several families of bivalve molluscs, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.
Bivalvia or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs that have laterally compressed soft bodies enclosed by a calcified exoskeleton consisting of a hinged pair of half-shells known as valves. As a group, bivalves have no head and lack some typical molluscan organs such as the radula and the odontophore. Their gills have evolved into ctenidia, specialised organs for feeding and breathing.
A byssus is a bundle of filaments secreted by many species of bivalve mollusc that function to attach the mollusc to a solid surface. Species from several families of clams have a byssus, including pen shells (Pinnidae), true mussels (Mytilidae), and Dreissenidae.
Sea silk is an extremely fine, rare, and valuable fabric that is made from the long silky filaments or byssus secreted by a gland in the foot of pen shells. The byssus is used by the mussel to attach itself to the sea bed.
The Pteriomorphia comprise a subclass of saltwater clams, marine bivalve molluscs. It contains several major orders, including the Arcida, Ostreida, Pectinida, Limida, Mytilida, and Pteriida. It also contains some extinct and probably basal families, such as the Evyanidae, Colpomyidae, Bakevelliidae, Cassianellidae, and Lithiotidae.
Atrina fragilis, the fan mussel, is a species of large saltwater clam, a marine bivalve mollusc in the family Pinnidae, the pen shells.
The Pinnidae are a taxonomic family of large saltwater clams sometimes known as pen shells. They are marine bivalve molluscs in the order Pteriida.
Pinna is a genus of bivalve molluscs belonging to the family Pinnidae. The type species of the genus is Pinna rudis.
Atrina is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae.
Atrina rigida, commonly called the rigid pen shell, is a species of bivalve mollusc in the family Pinnidae.
A bivalve shell is the enveloping exoskeleton or shell of a bivalve mollusc, composed of two hinged halves or valves. The two half-shells, called the "right valve" and "left valve", are joined by a ligament and usually articulate with one another using structures known as "teeth" which are situated along the hinge line. In many bivalve shells, the two valves are symmetrical along the hinge line — when truly symmetrical, such an animal is said to be equivalved; if the valves vary from each other in size or shape, inequivalved. If symmetrical front-to-back, the valves are said to be equilateral, and are otherwise considered inequilateral.
Ostrea lurida, common name the Olympia oyster, after Olympia, Washington in the Puget Sound area, is a species of small, edible oyster, a marine bivalve mollusk in the family Ostreidae. This species occurs on the northern Pacific coast of North America. Over the years the role of this edible species of oyster has been partly displaced by the cultivation of non-native edible oyster species.
Modiolus modiolus, common name northern horsemussel, is a species of marine bivalve mollusk in the family Mytilidae.
The Mediterranean mussel is a species of bivalve, a marine mollusc in the family Mytilidae. It is an invasive species in many parts of the world, and also an object of aquaculture.
Pinna carnea, commonly called the amber pen shell, is a species of bivalve mollusc in the family Pinnidae.
Hinge teeth are part of the anatomical structure of the inner surface of a bivalve shell, i.e. the shell of a bivalve mollusk. Bivalves by definition have two valves, which are joined together by a strong and flexible ligament situated on the hinge line at the dorsal edge of the shell. In life, the shell needs to be able to open slightly to allow the foot and siphons to protrude, and then close again, without the valves moving out of alignment with one another. To make this possible, in most cases the two valves are articulated using an arrangement of structures known as hinge teeth. Like the ligament, the hinge teeth are also situated along the hinge line of the shell, in most cases.
Pinctada mazatlanica is a species of tropical marine bivalve mollusc in the family Pteriidae, the pearl oysters. It is known by the English common names pearl oyster, Mazatlan pearl oyster, and Panama pearl oyster. Spanish common names include madre perla, and ostra perlifera panameña. This mollusc was first described to science in 1856 by conchologist Sylvannus Charles Thorp Hanley. Pinctada mazatlanica produces gem-quality pearls and was the basis of a pearling industry in the Gulf of California for centuries.
Pinna rudis, the rough pen shell or spiny fan-mussel, is a species of bivalve mollusc in the family Pinnidae. It is the type species of the genus Pinna. Knowledge about this is sparse, with an absence of specific studies and literature.
Pinna bicolor, also known as razorfish, razor clam, or pen shell, is a species of large saltwater clam in the family Pinnidae. It is commonly found in shallow waters up to 50 m (160 ft) deep. It can be found embedded in firm muddy intertidal sediments, seagrass beds, and reef flats along continental and island shores.
Atrina pectinata is a species of bivalves belonging to the family Pinnidae.