Pecten jacobaeus
Mediterranean scallop, pilgrim's shell, with 60 blue eyes.
Pecten jacobaeus, commonly called the Mediterranean scallop, is a marine bivalve mollusk in the family Pectinidae. It is an edible saltwater scallop. The shell typically reaches 120–140 mm in length, though the largest recorded specimen exceeds 210 mm. The two valves differ in shape: the lower valve, which rests on the seafloor, is very convex and pale, while the upper valve is flat and brown. Each valve bears 14 to 16 ribs with a roughly rectangular cross-section. The interior of the shell is smooth, like porcelain. Along the edge of the mantle are many short tentacles, interspersed with 60 blue, millimeter-sized lens eyes. By rapidly closing its valves, the scallop can swim several meters to escape danger. It feeds on plankton and other floating particles by filtering seawater through its gills.
This species appears to be endemic to the Mediterranean Sea, though it may be the same species as *Pecten maximus* (the great scallop), which has a wider range. The two are morphologically similar but have distinguishing features. Fossils of *Pecten jacobaeus* first appear at the start of the Pliocene and are common in Pliocene and Pleistocene deposits in Italy.
The scallop is collected commercially for food, often using a Rapido trawl. In Christian tradition, it is linked to Saint James (also known as James, son of Zebedee, or Saint Jacob), which gives the species its name *jacobaeus*. It is also called the "Pilgrim's scallop" because medieval pilgrims used the shells as cups.
Quick Facts
- Genus
- Pecten
- Species
- jacobaeus
Facts from the source article.
Lore & Background
Pecten jacobaeus usually reaches a length of about 120–140 mm, but the world record size reaches over 210 mm. The two valves have different shapes: the lower valve is very convex and light-colored, while the upper valve is flat and brown. They show 14 to 16 ribs 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 the two valves it can swim away several meters in case of danger. These scallops eat planktonic organisms and other floating food particles, which they obtain by filtering sea water with their gills.
This species appears to be endemic to the Mediterranean Sea, but it may be conspecific with Pecten maximus, 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 and are quite common in the Pliocene and Pleistocene deposits of Italy.
Reader's Guide
Pecten jacobaeus holds significance both as a commercially harvested food source and as a cultural symbol. Scallops of this species are collected commercially for human consumption using techniques such as the Rapido trawl. In popular culture, it is traditionally associated with Saint James, also known as James, son of Zebedee, or Saint Jacob, hence the specific name jacobaeus. It is also known as the 'Pilgrim's scallop', as the shells were used by pilgrims in the Middle Ages as a cup. The species is endemic to the Mediterranean Sea, though it may be conspecific with the great scallop Pecten maximus, which has a larger distribution. Its fossil record begins in the Pliocene, with common finds in Italian deposits. The scallop's distinctive morphology—a convex lower valve and flat upper valve, 14 to 16 ribs, and 60 blue eyes—enables it to swim away from danger. Its filtering diet of planktonic organisms and floating particles sustains its role in the marine ecosystem. The species was originally described by Linnaeus in 1758.
Did You Know?
- The world record size of Pecten jacobaeus reaches over 210 mm.
- It has 60 blue-millimeter lens eyes at the edge of its mantle.
- Fossils of this species first appear at the beginning of the Pliocene.
- Its shells were used by medieval pilgrims as a cup.
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