| Arca zebra | |
|---|---|
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| Interior and exterior of a shell of Arca zebra | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Order: | Arcida |
| Family: | Arcidae |
| Genus: | Arca |
| Species: | A. zebra |
| Binomial name | |
| 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.
This species is found along the Atlantic coast of North America, ranging from North Carolina to the West Indies and Bermuda. [2] It attaches itself to rocks or other hard substrates in shallow water with byssus threads.
The shell of Arca zebra is boldly striped in brown and white which gives it a resemblance to the wing of a wild turkey. The whole shell (when both valves are together) has also been likened to Noah's Ark. It is a sturdy shell growing up to 4 in (10 cm) long and 2 in wide. The umbones are separated by a shallow depression, and the hinge is long and straight with about 50 small teeth. There is coarse sculpturing fanning out from the umbones. The inside of the shell is whitish or pale mauve. [3]
Arca zebra is a filter feeder, taking in surrounding water and particulates through its reduced siphons and expelling water while consuming microscopic algae, diatoms, and phytoplankton. [4] [5]
Arca zebra is a protandric hermaphrodite, a type of sequential hermaphrodite with individuals starting out as males and developing female reproductive capacity later in the life cycle. [6] Reproduction is dependent on food availability and seasonal changes. The gonad tissues of Arca zebra change in mass throughout the year. The percentage of somatic tissue mass composed of gonad tissue mass sees a large increase from roughly 4% to 40% from May through late September and a large decrease from roughly 40% to 3% from October through January. The percentage then increases slightly from about 3% to 12% in February before decreasing to around 4% between March and April. Highest reproductive activity occurs around July through late September, when the gonad mass is at its greatest. [6]
Gonad development begins when the shells of Arca zebra are at 18-20mm, and full sexual maturity is reached when the shells are 50-55mm. Larger individuals have greater reproductive output. [6]
Arca zebra has two reproductive periods, one from June to July and the other in September. During each spawn, females can spawn up to four million eggs. Trochophore larvae, a type of planktonic larvae, begin to develop twelve hours after the eggs are fertilized. Six days after fertilization, the larvae begin to take on their adult shape. Eyespots develop seven days after fertilization, with the foot developing soon after. Around the same time the foot develops, food-seeking behavior in the substratum, the sediment at the bottom of the ocean floor, can be observed. Twelve days after fertilization, the larvae begin to settle; about 45% of the larvae reach this stage. Once the larvae reach adulthood, growth mainly happens in the summer, with growth in the summer happening about three times as quickly as in the winter. [6]
Like other marine bivalves, the biochemical composition in the tissues of Arca zebra fluctuate in response to environmental conditions including water temperature, nutrient availability, and contaminant concentration. The soft tissues see changes in protein, carbohydrate, and lipid concentrations. [7] Anthropogenic inputs into habitats of A. zebra can cause further fluctuations in the biochemical composition in the tissues. Lipophilic organic contaminants can accumulate in the tissues, and too high a concentration of these contaminants can interfere with normal lipid metabolism, impacting cell membrane synthesis and integrity as well as lysosomal activity. [7] Contaminant inputs can also influence the levels of lead, polychlorinated biphenyl, petroleum hydrocarbons, and tributyltin (TBT) in the tissues. TBT is utilized in some boat paints, contributing to its input into the marine habitats of A. zebra. Overexposure to TBT has deleterious impacts on A. zebra, including reduced feeding and increased energy expenditure. [8]
Arca zebra is the dominant species in its most well-observed habitats of Chacopata, Venezuela. It lives among a number of other species, most notably the Akoya pearl oyster, the leafy jewel box clam, the eared ark clam, and Modiolus squamosus. It is preyed upon by the apple murex, the West Indian murex, and the bent-beak murex, all species of predatory murex snails. [9]
Arca zebra also lives in association with a variety of microgastropod species, gastropods that measure less than 5mm in length. The most common ones found among A. zebra are some species of the top-snails, true whelks, and margin shells. However, their ecological relationship to A. zebra is not well understood as their small size makes these species difficult to study. [10]
Arca zebra has a large impact in the ecology of its habitat as beds of A. zebra serve as both food and shelter for a variety of other shallow water marine organisms. [11] Regions with greater Arca zebra bed density also see greater abundance, richness, and taxonomic distinctness in decapod crustaceans. The crevices that Arca zebra beds provide also support the development of richer faunal communities. [11]
Arca zebra are sometimes hitchhikers on live rock, ending up in saltwater fish tanks. They blow out debris in little plumes that may be noticed by the tank owner, leading to their discovery. [ citation needed ]
Arca zebra are caught for human consumption and canning. As efficient filter feeders, they convert large amounts of planktonic mass into biomass usable by humans. [9] A large bed spanning 70–80 km2 in the Cacopata region of the Araya Peninsula, Venezuela has been a site of fishing since 1940. The annual catch generally ranges from 15,792 to 33,986 tons per year but has reached 40,000 tons in the past. [12] It is a significant income source for Venezuelan artisanal fisheries. These fisheries employ non-selective fishing methods, resulting in significant bycatch of other molluscs, including the endangered music volute. [12] Bycatch also frequently includes the aforementioned Akoya pearl oyster, leafy jewel box clam, and apple murex as well as non-mollusc species. [13]
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. As a group, bivalves have no head and they lack some usual molluscan organs, like the radula and the odontophore. The class includes 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. Shipworms bore into wood, clay, or stone and live inside these substances.
Scallop is a common name that encompasses various species of marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name "scallop" is also sometimes applied to species in other closely related families within the superfamily Pectinoidea, which also includes the thorny oysters.
A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes: Gastropoda, Bivalvia and Cephalopoda.
The giant clams are the members of the clam genus Tridacna that are the largest living bivalve mollusks. There are several species of "giant clams" in the genus Tridacna, which are often misidentified for Tridacna gigas, the most commonly intended species referred to as "the giant clam".
Ark clam is the common name for a family of small to large-sized saltwater clams or marine bivalve molluscs in the family Arcidae. Ark clams vary both in shape and size. They number about 200 species worldwide.
The Unionidae are a family of freshwater mussels, the largest in the order Unionida, the bivalve molluscs sometimes known as river mussels, or simply as unionids.
The Pteriomorphia comprise a subclass of saltwater clams, marine bivalve molluscs. It contains several major orders, including the Arcida, Ostreida, Pectinida, Limida, Mytilida, and Pteriida. It also contains some extinct and probably basal families, such as the Evyanidae, Colpomyidae, Bakevelliidae, Cassianellidae, and Lithiotidae.
The maxima clam, also known as the small giant clam, is a species of bivalve mollusc found throughout the Indo-Pacific region.
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.
Freshwater bivalves are one kind of freshwater mollusc, along with freshwater snails. They are bivalves that live in fresh water as opposed to salt water, which is the main habitat type for bivalves.
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.
Perna perna, the brown mussel, is an economically important mussel, a bivalve mollusc belonging to the family Mytilidae. It is harvested as a food source but is also known to harbor toxins and cause damage to marine structures. It is native to the waters of Africa, Europe, and South America and was introduced in the waters of North America.
Mollusca is the second-largest phylum of invertebrate animals, after Arthropoda; members are known as molluscs or mollusks. Around 76,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied.
Chicoreus brevifrons, common name the West Indian murex, is a species of predatory sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails.
Donax hanleyanus, common name the wedge clam, is a marine bivalve mollusk species in the family Donacidae, the bean clams or wedge shells. It is widely distributed throughout the sandy beaches of the Atlantic coast of South America, from Brazil to Argentina.
Geukensia demissa is a species of mussel, a marine bivalve mollusk in the family Mytilidae, the true mussels. This species is native to the Atlantic coast of North America. The common names for this species include ribbed mussel, Atlantic ribbed marsh mussel and ribbed horsemussel. However, the common name ribbed mussel is also used for the Southern Hemisphere mussel Aulacomya atra. The appearance of the shell is grooved and oval in shape. The interior of this mussel is tinted purple
Pinna carnea, commonly called the amber pen shell, is a species of bivalve mollusc in the family Pinnidae.
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.
Macoma tenta, the narrowed macoma clam or elongate macoma is a species of clam, a marine bivalve mollusk (bivalvia) in the family Tellinidae and genus Macoma. Macoma tenta are one of two species of macoma clams that can be found in the Chesapeake Bay on the eastern shore of the United States in Maryland and Virginia. The macoma tenta like their cousin in the Chesapeake, the Macoma balthica or Baltic macoma clam, are small marine bivalves with thin, chalky white shells. They tend to live buried in the sandy or muddy areas of shallow water in the middle and lower Chesapeake Bay. Macoma clams are among the most abundant clams in the Chesapeake Bay. Macomas first appeared about 750,000 years ago.