Potamocorbula amurensis | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Bivalvia |
Order: | Myida |
Superfamily: | Myoidea |
Family: | Corbulidae |
Genus: | Potamocorbula |
Species: | P. amurensis |
Binomial name | |
Potamocorbula amurensis | |
Synonyms | |
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Potamocorbula amurensis is a species of small saltwater clam, a marine bivalve mollusc in the order Myida. Common names include the overbite clam, the Asian clam, the Amur River clam and the brackish-water corbula. The species is native to marine and brackish waters in the northern Pacific Ocean, its range extending from Siberia to China, Korea and Japan. It has become naturalised in San Francisco Bay.
Potamocorbula amurensis grows to a length of about 25 mm (1 in). The umbo is about half way along the hinge side of the shell and the shape of each valve is like a wide isosceles triangle with rounded corners. The right valve is rather larger than the left so that it overlaps a little at the margin, a fact that distinguishes this species from other similar clams. The surface is smooth with faint concentric sculpture that is parallel to the margin. The general colour is cream, yellowish or light brown. In young individuals, a dark-coloured periostracum covers the outer surface of each valve, but in older specimens this skin is largely worn away except for some wrinkled remnants at the valve margin. The part of the shell buried in the substrate is clean, whereas the exposed portion is often colonised by other organisms which stain it a dark colour. [2] [3]
The native range of Potamocorbula amurensis, "of the Amur River" is Siberia, China, Korea and Japan, between the latitudes of 53° N and 22° N. It has also become established in San Francisco Bay. [2] It lives subtidally and on intertidal mud flats partially buried in soft sediment. It is tolerant of a wide range of salinities, ranging from about one part to thirty-three parts per thousand. [4] In San Francisco Bay it is found subtidally in winter at 8 °C (46 °F) and in summer occurs on exposed mud flats at 23 °C (73 °F). It is believed that it was transported across the Pacific in ballast water and discharged accidentally into the Bay around 1986. [2]
Potamocorbula amurensis lies semi-submerged in sediment, fixing itself in place by means of a few byssal threads. It has two short siphons, through one of which (the upper, inhalant siphon) water is drawn into the shell. This water is passed over the gills, where oxygen and food particles such as bacteria, phytoplankton and zooplankton are removed. The water then passes out of the shell through the lower, exhalent siphon. This clam becomes sexually mature at the age of a few months. A single female can produce between 45,000 and 220,000 eggs. [2] These are fertilised externally and spend about 18 days as planktonic veliger larvae which can disperse to other areas, before settling on the seabed. [5]
There are concerns about Potamocorbula amurensis as an invasive species in San Francisco Bay, where it became established in the 1980s. It has thrived there and in some places it is present at densities of more than 10,000 individuals per square metre (10.8 square feet). [6] It out-competes native species and disrupts food chains by filtering phytoplankton and zooplankton from the water and consequently depriving juvenile fish of their planktonic food. [2] Another invasive species, the European green crab, Carcinus maenas, which arrived in the San Francisco Bay in around 1990, may control P. amurensis. The green crab voraciously eats bivalves, including P. amurensis, but may have other, unexpected, consequences. [6]
A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes: Gastropoda, Bivalvia and Cephalopoda.
Teredo navalis, commonly called the naval shipworm or turu, is a species of saltwater clam, a marine bivalve mollusc in the family Teredinidae. This species is the type species of the genus Teredo. Like other species in this family, this bivalve is called a shipworm because it resembles a worm in general appearance while at the anterior end it has a small shell with two valves, and it is adept at boring through wood.
Hippopus hippopus, also known as the Horse Hoof clam and Strawberry clam, is a species of giant clam in the Subfamily Tridacninae and the genus Hippopus. Hippopus is a delicacy in many Southeast Asian countries due to its high quality meat.
Tridacna crocea, the boring clam, crocus clam, crocea clam or saffron-coloured clam, is a species of bivalve in the family Cardiidae. It is native to the Indo-Pacific region. It is occasionally found in the aquarium trade where it is often simply referred to as crocea.
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The razor shell, Ensis magnus, also called razor clam, razor fish or spoot (colloquially), is a bivalve of the family Pharidae. It is found on sandy beaches in Canada and northern Europe.
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Corbulidae is a family of very small saltwater clams, marine bivalve molluscs in the order Myida.
Macoma nasuta, commonly known as the bent-nosed clam, is a species of bivalve found along the Pacific Ocean coast of North America. It is about 6 cm (2.4 in) long. It is often found buried in sands of 10–20 cm (3.9–7.9 in) in depth. This rounded clam has no radial ribs. Archaeological data supports the use of this species by Native Americans such as the Chumash peoples of central California.
Lajonkairia lajonkairii is an edible species of saltwater clam in the family Veneridae, the Venus clams. Common names include Manila clam, Japanese littleneck clam, Japanese cockle, and Japanese carpet shell. In Japan, it is known as asari. In Korea, it is known as bajirak.
Pseudofeces or pseudofaeces are a specialized method of expulsion that filter-feeding bivalve mollusks use in order to get rid of suspended particles such as particles of grit which cannot be used as food, and which have been rejected by the animal. The rejected particles are wrapped in mucus, and are then expelled without having passed through the digestive tract. Thus, although they may closely resemble the mollusk's real feces, they are not actually feces, hence the name pseudofeces, meaning false feces.
Mya truncata, common name the blunt gaper or truncate softshell, is a species of edible saltwater clam, a marine bivalve mollusk in the family Myidae.
Cyrtopleura costata, or the angel wing clam, is a bivalve mollusc in the family Pholadidae. It is found in shallow parts of the northwest Atlantic and also in the North Sea of Scotland coastline and west coast of the Adriatic Sea by a remote area in the Marche region in central Italy, living in the seabed, where it digs its burrows on a very slow revolving movement for years through soft sand and mud always to a max depth of 8ft but always below 3 feet (0.91 m) at the lowest tide.
Crassadoma is a genus of rock scallops, marine bivalve molluscs in the family Pectinidae. It is monotypic, the only species being Crassadoma gigantea, the rock scallop, giant rock scallop or purple-hinge rock scallop. Although the small juveniles are free-swimming, they soon become sessile, and are cemented to the substrate. These scallops occur in the eastern Pacific Ocean.
Venerupis corrugata, the pullet carpet shell, is a species of bivalve mollusc in the family Veneridae. It is found buried in the sediment on the sea bed in shallow parts of the eastern Atlantic Ocean. It is harvested for human consumption in Spain and other parts of Western Europe.
Saxidomus gigantea is a large, edible saltwater clam, a marine bivalve mollusk in the family Veneridae, the venus clams. It can be found along the western coast of North America, ranging from the Aleutian Islands to San Francisco Bay. Common names for this clam include butter clam, Washington clam, smooth Washington clam and money shell.
Fragum erugatum is a small species of cockle, a marine bivalve mollusc in the family Cardiidae. It is found in the shallow seas off the coast of Western Australia. It is commonly known as the Hamelin cockle, cardiid cockle or heart cockle.
Nuttallia obscurata, the purple mahogany clam, dark mahogany clam, varnish clam or savory clam, is a species of saltwater clam, a marine bivalve mollusk in the family Psammobiidae. It was first described to science by Lovell Augustus Reeve, a British conchologist, in 1857.
Potamocorbula is a genus of very small saltwater clams, marine bivalve molluscs in the subfamily Erodoninae of the family Corbulidae in the order Myida.
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