Ark clam is the common name for a family of small to large-sized saltwater clams or marine bivalve molluscs in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Arcidae. Ark clams vary both in shape and size. They number about 200 species worldwide. The shells of ark clams are often white or cream, but in some species, the shell is striped with, tinted with, or completely colored, a rich brown. In life the shell of most species has a top shell layer that is thick brown periostracum affixed to the harder calcareous part of the shell. In some species such as '' Barbatia'', this outer horny covering is tufted at the end of the shell into something that resembles a beard, hence the name ''Barbatia'' or bearded one. The group is known as "ark shells" because species such as '' Arca'' have a large flat area between the umbones which, in an undamaged shell, somewhat resembles a deck, with the rest of the shell perhaps illustrating an ancient wooden boat such as

Noah's ark Noah's Ark ( he, תיבת נח; Biblical Hebrew: ''Tevat Noaḥ'')The word "ark" in modern English comes from Old English ''aerca'', meaning a chest or box. (See Cresswell 2010, p.22) The Hebrew word for the vessel, ''teva'', occurs twice in ...

is thought to have been. All ark shells have a long straight hinge line with a single row of numerous small and unspecialized "teeth". This is known as a "taxodont dentition" and represents an ancient ancestor. This kind of hinge line is also found in the bivalve families Glycymerididae,

Nuculidae Nuculidae is a family of small saltwater clams in the order Nuculida. Species in this family are commonly known as nut clams. The nomenclature of the Western European species in this family is still uncertain. Their systematics has been based ma ...

and

Nuculanidae Nuculanidae is a family of small saltwater clams, marine bivalve molluscs in the order Nuculanida. Species in this family are found in all seas, from shallow to deep water. Genera and species Genera and species within the family Nuculanidae incl ...

. The thick outer skin or periostracum of an ark clam can act as

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

, such that the shells can sometimes look like stones when lying on the bottom. Large ark clams, such as ''

Arca zebra ''Arca zebra'', or the turkey wing ark clam (or simply turkey wing), is a bivalve mollusc in the family Arcidae, the ark clams. Description Distribution This species is found along the Atlantic coast of North America, ranging from North Caro ...

'', are commonly used as bait, as well as food, throughout the Caribbean. Some ark clams species, such as the

blood cockle ''Tegillarca granosa'' (also known as ''Anadara granosa'') is a species of ark clam known as the blood cockle or blood clam due to the red haemoglobin liquid inside the soft tissues. It is found throughout the Indo-Pacific region from the eastern ...

(''

Anadara granosa ''Tegillarca granosa'' (also known as ''Anadara granosa'') is a species of ark clam known as the blood cockle or blood clam due to the red haemoglobin liquid inside the soft tissues. It is found throughout the Indo-Pacific region from the eastern ...

'', a.k.a. ''

Tegillarca granosa ''Tegillarca granosa'' (also known as ''Anadara granosa'') is a species of ark clam known as the blood cockle or blood clam due to the red haemoglobin liquid inside the soft tissues. It is found throughout the Indo-Pacific region from the eastern ...

'') are raised in aquaculture, e.g. in the estuaries of China's

Fujian Fujian (; alternately romanized as Fukien or Hokkien) is a province on the southeastern coast of China. Fujian is bordered by Zhejiang to the north, Jiangxi to the west, Guangdong to the south, and the Taiwan Strait to the east. Its cap ...

coast. ''

'' was used as a food by Indigenous peoples living on the northern Australian coastline through at least the past ~4500 years, with extensive evidence preserved in the form of

shell mound A midden (also kitchen midden or shell heap) is an old dump for domestic waste which may consist of animal bone, human excrement, botanical material, mollusc shells, potsherds, lithics (especially debitage), and other artifacts and ecof ...

sites.

Genera

Genera within the family Arcidae include: * ''

Acar Acar is a type of vegetable pickle of Maritime Southeast Asia, most prevalent in Indonesia, Malaysia, Singapore and Brunei. It is a localised version of Indian '' achar''. It is known as atjar in Dutch cuisine, derived from Indonesian ''acar ...

Gray Grey (more common in British English) or gray (more common in American English) is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is "without color", because it can be composed o ...

, 1857 * ''

Anadara ''Anadara'' is a genus of saltwater bivalves, ark clams, in the family Arcidae. It is also called ''Scapharca''. This genus is known in the fossil record from the Cretaceous period to the Quaternary period (age range: 140.2 to 0.0 million yea ...

, 1847 * '' Arca''

Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

, 1758 * '' Barbatia''

, 1847 * '' Bathyarca'' Kobelt, 1891 * '' Bentharca'' Verrill and Bush, 1898 * ''

Larkinia ''Larkinia'' is a genus of saltwater clam Clam is a common name for several kinds of bivalve molluscs. The word is often applied only to those that are edible and live as infauna, spending most of their lives halfway buried in the sand of t ...

'' Reinhart, 1935 * '' Samacar'' Iredale, 1936 * '' Senilia''

, 1758 * ''

Tegillarca ''Tegillarca'' is a genus of molluscs of the family Arcidae, the Ark clams. Species Species of this genus include: * '' Tegillarca addita'' (Iredale, 1939) * '' Tegillarca aequilatera'' (Dunker, 1868) * '' Tegillarca bicors'' (Jonas in Philip ...

'' Iredale, 1939

References

External links

ITIS

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