Clam

Clams

Clam is an imprecisely defined common name variously used for certain bivalve mollusks or for all bivalve mollusks. As a member of the class Bivalvia (syn. Pelecypoda), clams typically are characterized by two-part calcareous shells that are hinged and more or less symmetrical and a laterally compressed muscular foot, which when extended into sediment (sand or mud), can swell with blood and form a hatchet-shaped anchor (Towle 1989). The term clam often is applied generally to those bivalves with the two shells of nearly equal size and that live in the sand or mud.

The term clam can be more precisely equated to any bivalve other than an oyster, mussel, or scallop and that has a more-and-less oval shape. Bunje (2001) uses the term for members of the subclass Heterodonta, but members of the order Unionoida in subclass Palaeoheterodonta often are known as freshwater clams (or as freshwater mussels). In the United States, the word clam often means any bivalve mollusk. In this later sense, the term includes oysters, mussels, and scallops.

The term clam often is applied to edible bivalves. Not all edible bivalves with the common name clam are round or oval in shape: the razor clam has an elongated shell whose shape suggests a straight razor.

• • Food

Anatomy

Maxima clam, Tridacna maxima.

Littleneck clams; the pictured molluscs are of the species Mercenaria mercenaria.

A clam's shell consists of two valves which are connected by a hinge joint and a ligament that can be external or internal. Two adductor muscles close the shells. The clam has no head, and usually has no eyes, (scallops are a notable exception), but a clam does have kidneys, a heart, a mouth, and an anus. Clams have bilateral symmetry. Another known species is the "Bearded" clam. It is usually found in dark, moist caverns south of the equator. If you are looking to cook with this species, the younger the better will make your chowder a delicacy! Just ask Brent, of Dart Transit Egan MN. He once won a contest for his clam chowder. When asked for his secret Brent only commented, "Clam and Barb-Knuckles is a tasty mixture!" He must have meant barnacles, but we here at Wikipedia prefer to include the right quote.

Clams, like most mollusks, also have open circulatory systems, which means that their organs are surrounded by watery blood that contains nutrients and oxygen. Clams eat plankton by filter feeding, and they themselves are eaten by small sharks and squid.

In culinary use, the term "clam" most often refers to the hard clam Mercenaria mercenaria but it may refer to several other species such as the soft-shell clam, Mya arenaria. Clams can be eaten raw, steamed, boiled, baked or fried; the method of preparation depends partly on size and species. Clam chowder is a popular soup in the U.S. and Canada. In Italy, clams are often an ingredient of mixed seafood dishes, or are eaten together with pasta.

The Maxima clam Tridacna maxima, a species of giant clam, is popular with saltwater aquarium hobbyists.

The Moche people of ancient Peru worshiped the sea and its animals. They often depicted clams in their art.

The word "clam" has no real taxonomic significance in biology.

In October 2007 an Arctica islandica clam caught off the coast of Iceland was discovered to be at least 405 years old,and was declared the world's oldest living animal by researchers from Bangor University, see Ming (clam).

Examples of clams

File:Shelllarcomuseum.jpg

Moche clam. 200 C.E. Larco Museum Collection Lima, Peru.

• Ark clams, family Arcidae
• Nut clams or pointed nut clams, family Nuculidae
• Duck clams or trough shells, family Mactridae
• Marsh clams, family Corbiculidae
• File clams, family Limidae
• Hard clam or Northern Quahog: Mercenaria mercenaria
• Soft clam: Mya arenaria
• Surf clam: Spisula solidissima
• Ocean quahog: Arctica islandica
• Pacific razor clam: Siliqua patula
• Giant clam: Tridacna gigas
• Asian or Asiatic clam: genus Corbicula
• Peppery furrow shell: Scrobicularia plana
• Pismo clam: Tivela stultorum (8 inch shell on display in the Pismo Beach Chamber of Commerce)
• Geoduck clam: Panopea abrupta or Panope generosa (largest burrowing clam in the world)
• Atlantic jackknife clam: Ensis directus

Culinary uses

File:2005clam.cockle.arkshell.PNG

Clam, cockle and arkshell output in 2005

See also

Wikimedia Commons has media related to:

Bivalvia

• Clam bake
• Clam boil
• Fried clams
• Clam Chowder

External Links

• Deep In The Ocean A Clam That Acts Like A Plant Science Daily March 2 2007
• How to Shuck Hard Shell Clams

Credits

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