''Pecten jacobaeus'', the Mediterranean scallop, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of scallop, an edible saltwater scallop, a marine bivalve mollusc in the family

Pectinidae Scallop () is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name "scallop" is also sometimes applied to species in other closely related families ...

, the scallops.World Register of Marine species
/ref> Pectinidae - Pecten jacobaeus

Description

''Pecten jacobaeus'' usually reaches a length of about , but the world record size reaches over 210 mm.
/ref> The two valves have different shapes. The lower valve, with which the animal rests on the bottom, is very convex and light-colored, while the upper valve is flat and brown. They show 14 to 16 ribs (radial wrinkles) with a more or less rectangular cross section. The inside of the valves is porcelain-like smooth. The mollusc has at the edge of the mantle many short tentacles, between which there are a total of 60 blue-millimeter lens eyes. By quickly closing of the two valves it can swim away several meters in case of danger. These scallops eat

plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...

ic organisms and other floating food particles, which they obtain by filtering sea water with their

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

Distribution

This species appears to be endemic to the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

, but it may be conspecific with ''

Pecten maximus ''Pecten maximus'', common names the great scallop, king scallop, St James shell or escallop, is a northeast Atlantic species of scallop, an edible saltwater clam, a marine bivalve mollusc in the family Pectinidae. This is the type species of ...

'', the great scallop, which has a larger distribution. Although these two species are morphologically similar, they present distinguishing features. Fossils of ''Pecten jacobaeus'' first appear at the beginning of the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...

deposits of Italy.

Commercial value

Scallops of this species are collected commercially for human consumption using such techniques as the Rapido trawl.

Popular culture

In a Christian context, this species is considered to be the scallop which is traditionally associated with Saint James, also known as

James, son of Zebedee James the Great, also known as James, son of Zebedee, Saint James the Great, Saint James the Greater, Saint James the Elder, or Saint Jacob (Aramaic ܝܥܩܘܒ ܒܪ ܙܒܕܝ, Arabic يعقوب, Hebrew בן זבדי , '' Yaʿăqōḇ'', Latin '' ...

, also known as Saint Jacob, hence the specific name ''jacobaeus''. It is also known as the "Pilgrim's scallop", as the shells were used by the pilgrims in the Middle Ages as a cup.

References

* C. Linnaeus. 1758. Systema Naturae per Regna Tria Naturae, secundum Classes, Ordines, Genera, Species, cum Characteribus, Differentiis, Synonymis, Locis. Tomus I. Editio decima, reformata. Laurentii Salvii, Holmiae (Lars Salvius, Stockholm) * Guido T. Poppe und Y. Goto: European Seashells. Vol II (Scaphopoda, Bivalvia, Cephalopoda). 221 S., Verlag Christa Hemmen, Wiesbaden, 1993

External links