''Argopecten gibbus'', the Atlantic calico scallop, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of medium-sized edible marine

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

in the family

Pectinidae Scallop () is a common name that encompasses various species of Marine (ocean), marine bivalve mollusc, molluscs in the Taxonomy (biology), taxonomic Family (biology), family Pectinidae, the scallops. However, the common name "scallop" is also ...

, the scallops. This species was once the basis of an important fishery, but in recent years catches have been low.Atlantic calico scallop in Smithsonian museum
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Description

This species grows up to three inches in maximum width, and is similar in shape and sculpturing to the Atlantic bay scallop. Both valves of the shell are cupped. The shell near the hinge is extended into "ears", as is the case in all scallops. The shell of the Atlantic calico scallop has about 20 radial ribs, which are sometimes roughened by growth lines. The exterior coloration of the upper (left) valve of this species is most typically a mottled pattern of purple on a cream background. The lower (right) valve of this scallop is usually whitish with small reddish or purple spotting on the sides. The interior of the shell is white, often with some beige coloration on the "ears" and top edge. The eye-catching color of the shell of this species gave rise to its popular name; in the US, "calico" was for many years an inexpensive but colorful fabric printed with small flower patterns. The name is no longer in practice within the US.

File:Argopecten gibbus 01.jpg, Right valve File:Argopecten gibbus 02.jpg, Left valve

Habitat

The Atlantic calico scallop ranges from

Delaware Delaware ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic and South Atlantic states, South Atlantic regions of the United States. It borders Maryland to its south and west, Pennsylvania to its north, New Jersey ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

, and is still sometimes fished commercially. It is not found in bays; instead it lives in open water up to 100-foot depths. The shells are commonly found washed up on ocean beaches. Valve color and shell morphometry distinguish calico scallops from related species. In the

Indian River Lagoon The Indian River Lagoon is a grouping of three lagoons: the Mosquito Lagoon, the Banana River, and the Indian River, on the Atlantic Coast of Florida; one of the most biodiverse estuaries in the Northern Hemisphere and is home to more than 4, ...

in Florida, two other scallops occur: the bay scallop, ''(

Argopecten irradians ''Argopecten irradians'', formerly classified as '' Aequipecten irradians'', common names Atlantic bay scallop, bay scallop, and blue-eyed scallop, is a species of scallop in the family Pectinidae. An edible saltwater clam, it is native to the ...

''), which generally has a uniform gray to gray-brown coloration with distinct convexity of the right (lower) valve. The other is the rough scallop, (''Aequipecten muscosus''), which has unequal 'ears' and has sharp scales on the lower surface of the ribs. The color of the rough scallop is yellow, orange, red or brownish.

References

The superfamily Pectinacea and scallops
*
North Carolina Sea Grant

External links

The Evolution of the Argopecten gibbus Stock (Mollusca: Bivalvia), with Emphasis on the Tertiary and Quaternary Species of Eastern North America
{{Taxonbar, from=Q3017111 gibbus Molluscs described in 1767 Taxa named by Carl Linnaeus