| Mya truncata | |
|---|---|
 | |
| Shell of Mya truncata, on display at the Museo Civico di Storia Naturale di Milano | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Subclass: | Heterodonta |
| Order: | Myida |
| Superfamily: | Myoidea |
| Family: | Myidae |
| Genus: | Mya |
| Species: | M. truncata |
| Binomial name | |
| Mya truncata | |
| Synonyms | |
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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.
Shells of Mya truncata can reach a size of about 2.5–7.5 centimetres (0.98–2.95 in). [1] [2] These bivalves are similar to the soft-shell clams ( Mya arenaria ), but usually they are smaller. Moreover, their shells are less elongated. [1]
Valves are rounded in the anterior end and truncated in the posterior end, with a large gape allowing the passage of an extensible siphon that can reach four times the length of the shell. The siphon can be retracted completely into the shell. The two valves are triangular and convex, but the right valve is more convex than the left one. The siphon is protected by a horny sheath and it is provided with small tentacles at its end. [1]
The outer surface of the valves is covered with concentric growth lines. It is whitish, while the outermost layer of the valves (periostracum) may be yellowish, light olive or dark brown. The hinge of the left valve shows a spoon-shaped projection, to which the ligaments are attached. The pallial sinus is deep and broad. [1] [3]
Reproduction is sexual, the gametes of both sexes being expelled into the water, then the free larvae attach themselves to rocks. These clams filter the sea water in order to feed on bacteria, diatoms and larvae of invertebrates. In some years, the reproductive cycle fails completely.
These clams are the main food of the walrusses ( Odobenus rosmarus ). They feed on these clams by raking the mud with their tusks and sieving out the clams.
This species is widespread over the Arctic seas and extends to the Bay of Biscay, to the West Atlantic coast and to Sakhalin on the Pacific coast. It has been reported also in the waters around Japan. [1] [2] [4] Mya truncata lives from the lower shore up to depths of 70 m, burrowed in sand or sandy mud. [1] [2]
Bivalvia, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. Bivalves as a group have no head and they lack some usual molluscan organs like the radula and the odontophore. They include the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. The shipworms bore into wood, clay, or stone and live inside these substances.
A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes: Gastropoda, Bivalvia and Cephalopoda.
Soft-shell clams or sand gaper, scientific name Mya arenaria, popularly called "steamers", "softshells", "piss clams", "Ipswich clams", or "Essex clams" are a species of edible saltwater clam, a marine bivalve mollusk in the family Myidae.
Pholadidae, known as piddocks or angelwings, are a family of bivalve molluscs similar to a clam.
Mactridae, common name the trough shells or duck clams, is a family of saltwater clams, marine bivalve mollusks in the order Venerida.
Mya is a genus of saltwater clams, marine bivalve molluscs in the family Myidae. They are widespread and abundant in northern waters. Commonly known as Ipswich clams, soft-shell clam or steamers, they are routinely used as a food source for humans.
A bivalve shell is part of the body, the exoskeleton or shell, of a bivalve mollusk. In life, the shell of this class of mollusks is composed of two hinged parts or valves. Bivalves are very common in essentially all aquatic locales, including saltwater, brackish water, and freshwater. The shells of bivalves commonly wash up on beaches and along the edges of lakes, rivers, and streams. Bivalves by definition possess two shells or valves, a "right valve" and a "left valve", that are joined by a ligament. The two valves usually articulate with one another using structures known as "teeth" which are situated along the hinge line. In many bivalve shells, the two valves are symmetrical along the hinge line—when truly symmetrical, such an animal is said to be equivalved; if the valves vary from each other in size or shape, inequivalved. If symmetrical front-to-back, the valves are said to be equilateral, and are otherwise considered inequilateral.
The grooved carpet shell, or Palourde clam, Ruditapes decussatus, or Venerupis decussatus, is a clam or bivalve mollusc in the family Veneridae. It is distributed worldwide and due to its ecological and economic interest has been proposed as a bioindicator.
Ensis ensis, or the sword razor, is a razor clam, a marine bivalve mollusc in the family Pharidae. It lives buried in the sand and is found off the coasts of northwest Europe.
Fabulina fabula, the bean-like tellin, is a species of marine bivalve mollusc in the family Tellinidae. It is found off the coasts of northwest Europe, where it lives buried in sandy sediments.
Abra alba, or the white furrow shell, is a species of bivalve mollusc in the family Semelidae. It occurs in the northeastern Atlantic Ocean and the Mediterranean Sea, where it lives on the floor in shallow areas buried in soft sediments.
Phaxas pellucidus, the transparent razor shell, is a species of marine bivalve mollusc in the family Pharidae. It is found buried in the seabed in coastal waters of northwest Europe, often in great numbers.
Lutraria is a genus of medium-sized marine bivalve mollusks or clams, commonly known as otter shells.
Lutraria lutraria is a species of large marine bivalve mollusc in the family Mactridae. Its common names include the otter shell and the common otter shell. It occurs in coastal regions of the north east Atlantic Ocean where it lives buried in the sand.
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.
Thracia convexa is a bivalve mollusc in the family Thraciidae.
Mulinia lateralis, the dwarf surf clam or coot clam, is a species of small saltwater clam, a bivalve mollusc in the family Mactridae. It occurs in the western Atlantic Ocean and the Caribbean Sea.
Laternula elliptica is a species of saltwater clam, a marine bivalve mollusc in the family Laternulidae, the lantern shells. It is the largest bivalve found under the surface of the seabed in the Southern 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.
Solecurtus strigilatus, also known as the rosy razor clam, is a species of saltwater clam, a marine bivalve mollusc in the family Solecurtidae. This mollusc is a suspension feeder and can burrow with great rapidity to escape predators. It is an unusual bivalve in that its shell valves are too small to contain all the soft tissue, and the animal is unable to retreat into its shell.