Cyrtopleura costata
Encyclopedia
Cyrtopleura costata or the angel wing clam is a bivalve
mollusc
in the family
Pholadidae. It is found in shallow parts of the north west Atlantic living in the seabed where it burrows through sand and mud to a depth of up to 3 foot (0.9144 m).
, a thin grey protective layer. This coating has usually been abraded when the empty shells are washed up on the beach, and the valves are usually found singly because the muscles that hold them together are weak. Internally, the live mollusc has a powerful muscular foot and a pair of long, fused siphons. These siphons are unable to retract back into the shell and as a result, the two valves permanently gape apart.
between Cape Cod
and the Gulf of Mexico
. It is also found in the West Indies, Central America
and as far south as Brazil
. It is commonest in the intertidal zone
and just below low water mark.
. The siphons extend to the surface of the substrate
and water is drawn in through one and expelled through the other with microalgae and zooplankton
being filtered out as the water passes through the gills. Respiration takes place at the same time. Cilia then waft the food particles to the mouth.
Spawning usually takes place in summer. Gamete
s are passed out of the exhalent siphon and fertilisation takes place externally. After hatching, eggs
develop into veliger
larvae which are plankton
ic. After 16 to 21 days these undergo metamorphosis
into a pediveliger stage and settle out onto a soft substrate such as sand. There they become juveniles and start burrowing.
and Puerto Rico
. It is a fast growing species and it has been investigated for possible use in commercial aquaculture
. Under optimal conditions it was found that the larvae were ready to undergo metamorphosis
after 12 days and settlement could be triggered by use of a dilute solution of epinephrine
. The clams could reach a marketable size of 6 centimetres (2.4 in) within 6 months.
Bivalvia
Bivalvia is a taxonomic class of marine and freshwater molluscs. This class includes clams, oysters, mussels, scallops, and many other families of molluscs that have two hinged shells...
mollusc
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...
in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Pholadidae. It is found in shallow parts of the north west Atlantic living in the seabed where it burrows through sand and mud to a depth of up to 3 foot (0.9144 m).
Description
Cyrtopleura costata has a pair of brittle, asymmetric white valves and can grow to about 7 inches (17.8 cm) in length. The anterior end is elongated and has a rounded point which is used for digging through the substrate. The posterior end is truncated and rounded and near the beak has an apophysis, a wing-like flange, which helps provide an attachment for the foot muscles. On the anterior side of the beak, the margin is smooth and bent slightly upwards. The whole valve has finely sculptured radial ribs which intercept with a series of concentric growth rings parallel with the margin. In the living animal, the valves are covered by the periostracumPeriostracum
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...
, a thin grey protective layer. This coating has usually been abraded when the empty shells are washed up on the beach, and the valves are usually found singly because the muscles that hold them together are weak. Internally, the live mollusc has a powerful muscular foot and a pair of long, fused siphons. These siphons are unable to retract back into the shell and as a result, the two valves permanently gape apart.
Distribution
Cyrtopleura costata is found in shallow seas in the north west Atlantic OceanAtlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
between Cape Cod
Cape Cod
Cape Cod, often referred to locally as simply the Cape, is a cape in the easternmost portion of the state of Massachusetts, in the Northeastern United States...
and the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
. It is also found in the West Indies, Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
and as far south as Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
. It is commonest in the intertidal zone
Intertidal zone
The intertidal zone is the area that is above water at low tide and under water at high tide . This area can include many different types of habitats, with many types of animals like starfish, sea urchins, and some species of coral...
and just below low water mark.
Biology
Cyrtopleura costata lives beneath the surface of the sea bed. It is able to bore through sand, mud, wood, clay and even soft rock using a twisting motion of its pointed, anterior end assisted by jets of water ejected from the mantle cavity. It is a filter feederFilter feeder
Filter feeders are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish and some sharks. Some birds,...
. The siphons extend to the surface of the substrate
Substrate (biology)
In biology a substrate is the surface a plant or animal lives upon and grows on. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock can be substrate for another animal that lives on top of the algae. See also substrate .-External...
and water is drawn in through one and expelled through the other with microalgae and zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
being filtered out as the water passes through the gills. Respiration takes place at the same time. Cilia then waft the food particles to the mouth.
Spawning usually takes place in summer. Gamete
Gamete
A gamete is a cell that fuses with another cell during fertilization in organisms that reproduce sexually...
s are passed out of the exhalent siphon and fertilisation takes place externally. After hatching, eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
develop into veliger
Veliger
A veliger is the planktonic larva of many kinds of marine and freshwater gastropod molluscs, as well as most bivalve mollusks.- Description :...
larvae which are plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
ic. After 16 to 21 days these undergo metamorphosis
Metamorphosis
Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation...
into a pediveliger stage and settle out onto a soft substrate such as sand. There they become juveniles and start burrowing.
Uses
Cyrtopleura costata is used as food in CubaCuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
and Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
. It is a fast growing species and it has been investigated for possible use in commercial aquaculture
Aquaculture
Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...
. Under optimal conditions it was found that the larvae were ready to undergo metamorphosis
Metamorphosis
Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation...
after 12 days and settlement could be triggered by use of a dilute solution of epinephrine
Epinephrine
Epinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...
. The clams could reach a marketable size of 6 centimetres (2.4 in) within 6 months.