One species of abra clam (Abra profundorum), however, has been taken in the Pacific Ocean at a depth of more than 4,800 metres (16,000 feet). (b) A giant clam. The Bivalvia Gastropods and bivalves may be the most common mollusks, but cephalopods (the family that includes octopuses, squids, and cuttlefish) are by far the most advanced. Updates? Surface-burrowing species may have an external shell sculpture of radial ribs and concentric lines, with projections that strengthen the shell against predators and damage. Learn. The valves are connected to one another at a hinge. These … The majority are filter feeders and have no head or radula. For more information on clam species and groups, see ark shell; coquina clam; gaper clam; geoduck; razor clam. In fact, there are well over 10,000 described species of bivalve, found from the deepest depths of the oceans, to the streams in your backyard. Terms in this set (11) Key Characteristics. M. mercenaria is about 7.5 to 12.5 cm (3 to 5 inches) long. The mantle B. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. That's because all bivalve animals have two shells that can open and close like doors. The northern quahog (Mercenaria mercenaria), also known as the cherrystone clam, littleneck clam, or hard-shell clam, and the southern quahog (M. campechiensis) belong to the family of venus clams (Veneridae). Members of the class Bivalvia are mostly gonochoric, some are protandric hermaphrodites. A radula C. A shell D. Gills E. Open circulation. Others, such as cockles and clams on soft shores and mussels and oysters on rocky coasts, can occur in densities high enough that they dominate entire habitats and assume important roles in nutrient cycles. Some scallops (family Pectinidae) are also cemented, but others lie on soft sediments in coastal waters and at abyssal depths. Our editors will review what you’ve submitted and determine whether to revise the article. In deeper-burrowing species the shells are laterally compressed, permitting more rapid movement through the sediments. The dingy white shell, which is thick and rounded and has prominent concentric lines, is found in the intertidal zone from the Gulf of St. Lawrence to the Gulf of Mexico; it is the most important food clam of the Atlantic coast. Many species, including the quahog, geoduck, and soft-shell clam, are edible. Articles from Britannica Encyclopedias for elementary and high school students. a class of marine and freshwater molluscs with laterally compressed bodies enclosed by a shell in two hinged parts. The shell is dirty white, oval, and 7.5 to 15 cm long. Common clams not ordinarily eaten include long siphon clams (Sanguinolariidae), wedge clams (Mesodesmatidae), basket clams (Corbulidae), slender clams (Pandoridae), perforated clams (Thraciidae), and boring clams (see piddock). Articles from Britannica Encyclopedias for elementary and high school students. Updates? It occurs in the intertidal zone from Chesapeake Bay to the West Indies. The soft-shell clam (Mya arenaria), also known as the longneck clam, or steamer, is a common ingredient of soups and chowders. In other species, such as the clams, the foot has become modified for rapid and effective digging, and the folds of the mantle tissue have developed into long siphons. The Pacific geoduck (Panopea generosa), found on the coast from Alaska to Baja California, burrows 60 to 90 cm into the mud of tidal flats. 833). Bivalves thus occur at all latitudes and depths, although none are planktonic. Most bivalves are marine and occur at all depths in or upon virtually all substrates. ohaneze ndi-igbo, new york chapter. Bivalves formed important components of marine communities since they first diversified, especially in shallow-water m… There are no terrestrial bivalves, although some high-intertidal and freshwater species can withstand drought conditions. Members Of Class Bivalvia In Phylum Mollusca Are So-named Because They Have "valves," Which Is A Term For The Two Halves Of Their A. Gills B. Labial Palps C. Shells D. Digestive Glands 2. By limiting shell thickness (which reduces weight), smoothing the shell contours (which reduces drag), and assuming an aerofoil-like leading edge, such scallops can awkwardly swim several metres at a time. In most surface-burrowing species (the hypothetical ancestral habit) the shells are small, spherical or oval, with equal left and right valves. Life cycle: Embryos develop into free-swimming trocophore larvae, succeeded by the bivalve veliger, resembling a miniature clam (Ref. Both these features allow the animals to burrow deeply within sand, mud, and other substrates (even into wood and rock). In addition, a few species of clams do not feed in the normal sense; they gain their nutrition from sulfur-oxidizing bacteria that live symbiotically in the gill tissue. (a) A species of sea scallop. The size of clams ranges from 0.1 mm (0.004 inch) in Condylocardia to 1.2 metres across in the giant clam (Tridacna gigas) of the Pacific and Indian oceans. The shells of the most efficient burrowers, the razor clams Ensis and Solen, are laterally compressed, smooth, and elongated. Phylum Mollusca, Class Bivalvia. Clam, in general, any member of the invertebrate class Bivalvia—mollusks with a bivalved shell (i.e., one with two separate sections). You likely know them as shellfish. Snapshot: Bivalvia. B. NO RADULA laterally compressed bodies shell composed of two valves large mantle cavity well developed gills. In shallow seas, bivalves are often dominant on rocky and sandy coasts and are also important in offshore sediments. Common names of representatives: clams, scallops, oysters, mussels. The gills have evolved into specialised organs for feeding and breathing. important members of most marine and freshwater ecosystems. Write. With more than 9000 living species, Bivalvia has a rich molluscan species diversity. Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... …more than 15,000 species of clams, oysters, mussels, scallops, and other members of the phylum Mollusca characterized by a shell that is... Get exclusive access to content from our 1768 First Edition with your subscription. The composition and systematic position of the family Cardiniidae are discussed, and the conclusion is reached that, while Cardinia itself was an early representative of the order Heterodontida, other genera which were included in the family by Zittel, its author, were unrelated forms belonging to a different order, the Naiadida. To be expected within a class comprising more than 15,000 living species, abundance varies considerably. 833). Flashcards. Throughout history, bivalves have been one of the most important marine animals to humans. Omissions? Corrections? The Atlantic geoduck (P. bitruncata), similar to the Pacific species, occurs from the coast of North Carolina to the Gulf of Mexico. Omissions? Habitat(s): marine (salt water), freshwater (lakes, rivers, and streams). Such a shell form and habit evolved first within sediments (endobyssate), where the byssus serves for anchorage and protection when formed into an enclosing nest. The taxonomic term Bivalvia was first used by Linnaeus in the 10th edition of his Systema Naturae in 1758 to refer to animals having shells composed of two valves. These are the scientists who first described the taxon and so should be retained where they are. They are protected from predators within such substrata but are still able to feed and breathe using their long siphons. Most bivalves spend most of their time in one location. Bivalves usually live on or in sandy or muddy bottoms. PLAY. Please select which sections you would like to print: Corrections? It begins in the Cambrian period (544–505 million years ago [mya]) with a laterally compressed stenothecid monoplacophoran (primitive single-shelled marine mollusk) as the most likely immediate ancestor. The two rigid parts of the shell (Figure 4A) are hinged together. Similar to the gastropods, there are a few species of bivalves that have completely lost their shells through evolution. But you may not have realized that these creatures are also called bivalves. 271). The northern coquina (D. fossor), 6 to 12 mm long, is yellowish white with bluish rays and inhabits shallow waters from Long Island to Cape May, New Jersey. Scallops, Clams, oysters, mussels. Feeding type(s): mostly suspension feeders; some deposit feeders and carnivores Geological range: Cambrian to today. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. Hypernyms ("class Bivalvia" is a kind of...): class ((biology) a taxonomic group containing one or more orders) Meronyms (members of "class Bivalvia"): Anomiidae; family Anomiidae (saddle oysters) family Pholadidae; Pholadidae (a family of Bivalvia) family Teredinidae; Teredinidae (shipworms) family Pectinidae; Pectinidae (scallops) Oyster C. Clam D. Snail E. Scallops. Bivalves are known by a variety of common names, depending on species, or species group; Clams, Cockles, Fan Shells, Mussels, Oysters, Scallops and Shipworms are all species of bilvalves. The byssus is a larval feature that is retained by adults of some bivalve groups, such as the true mussels (family Mytilidae) of marine and estuarine shores and the family Dreissenidae of fresh and estuarine waters. They can disperse more widely as they remain planktonic for a much longer time. Anatomy. Of these, 21 have…, A clamshell is an example of a simple system in which a rigid skeleton is worked by muscles. The best example of this is the windowpane shell Placuna. Bivalvia is a class of marine and freshwater molluscs with laterally compressed bodies enclosed by a shell in two hinged parts. Bivalves include clams, oysters, mussels, scallops, and numerous other families of shells. By the Middle Ordovician period (about 460 mya), recognizable members of all modern subclasses had appeared. They rarely travel over the bottom as do some other bivalves. True clams, in the strict sense, are bivalves with equal shells closed by two adductor muscles situated at opposite ends of the shell, and with a powerful, muscular, burrowing foot. for all people of igbo origin STUDY. Created by. Professor of Ecology and Biodiversity; Director, Swire Institute of Marine Science, University of Hong Kong. They include clams, oysters, mussels and scallops and most are filter feeders. All bivalves are aquatic, living at all depths of the sea and in brackish waters and freshwaters . Bivalvia | Bivalves. Label The Diagram (Fig. Class Bivalvia. 1) Of A Clam (Phylum Mollusca) With The Following: A. In addition, bivalves bore into soft shales and compacted muds but may be important also in the bioerosion of corals. Members of the molluscan class Bivalvia (formerly, Pelecypoda) are known commonly as bivalves and include clams, oysters, mussels, and scallops. Marine members of the Bivalvia class are molluscs that have laterally flattened bodies enclosed by a shell formed of two hinged parts. A triangular form, ventral flattening, and secure attachment to firm substrates by byssal threads (byssus; proteinaceous threads secreted by a gland on the foot) have allowed certain bivalves to colonize hard surfaces on wave-swept shores. Eggs are usually shed by the female into the water and fertilized there by sperm released from the male. Most Sphaerium species are large, about 8 to 20 mm; Pisidium species are the smallest, most ranging in shell length from about 2 to 6 mm; and most Musculium species are intermediate in size, about 8 to 10 mm in shell length, and the shells are thin and fragile. As in snails, the protective shells of bivalve molluscs are composed of a thick calcareous matrix overlain with a thin, protein-based periostracum. Some freshwater species, when exposed to the air, can gape the shell slightly and gas exchange can take place. In keeping with a largely sedentary and deposit-feeding or suspension-feeding lifestyle, bivalves have lost the head and the radular rasping organ typical of most mollusks. They occur at abyssal and hadal depths, either burrowing or surface-dwelling, and are important elements of the midoceanic rift fauna. D. Turbellarian flatworms have a distict head. The valves are connected to one another at a hinge. The rasping tongue, the radula, is present in which molluscan group? Get exclusive access to content from our 1768 First Edition with your subscription. More recently, the class was known as Pelecypoda, meaning "axe-foot" (based on the shape of the foot of the animal when extended). Members of the class Bivalvia are mostly gonochoric, some are protandric hermaphrodites. Our editors will review what you’ve submitted and determine whether to revise the article. A bivalve is an animal belonging to the class Bivalvia. Lives life upsidedown reduced head mouth surrounded by palps muscular foot for burrowing … These clams are common at marine hydrothermal vents and in sulfide-rich sediments. Members of the class Bivalvia. Author of. Let us know if you have suggestions to improve this article (requires login). From the simple burrowing, equivalve ancestor, the various bivalve groups have repeatedly evolved an elongated, triangular or circular shell; thus, similar body adaptations have been responses to similar modes of life. Most marine bivalves go through a trochophore stage before turning into a free-swimming veliger larva. A. Bivalve B. Attached to roots of Rhizophora mangle, rocks or other oyster shells. As the name implies, bivalves have two half-shells called valves that are connected by a dorsal hinge region. Such an animal may have a life span of about 40 years. More than 15,000 living species of bivalves are known, of which about 500 live in fresh water; the others occur in all seas. There are also estuarine bivalves, and two important families, the Unionidae and Corbiculidae, are predominantly freshwater with complicated reproductive cycles. Bivalves have two shells, connected by a flexible ligament, which encase and shield the soft vulnerable parts of the creature. PDF | On Mar 25, 2008, Gonzalo Giribet published Bivalvia | Find, read and cite all the research you need on ResearchGate Commensal and parasitic species are small, often highly host-specific, and comprise some of the rarest animals. Shells of species within this class range from about 0.5 to 15 cm in length. Bivalvia Class Bivalvia members have two shells which are held together by one or two strong muscles. Bivalves are aquatic animals, and different species of bivalve… The valves are connected to one another at a hinge. All of the following are either structures or characteristics of members of the Class Bivalvia of the Phylum Mollusca except A. Clams burrow in mud or sand while mussels use sticky threads to bind to rocks. It is mostly intertidal or shallow-subtidal species (Ref. All have shells composed of two pieces known as valves. Clams, mussels, oysters, and scallops are members to the class Bivalvia (or Pelecypodia). Gravity. M. campechiensis, the southern quahog, is about 7.5 to 15 cm long and has a heavy, white, plump shell. The extinct genus Myalina is important for stratigraphic correlations. All 15,000 known species of bivalves are aquatic in nature, with close to 80% being marine (saltwater environments). They have been used for food, jewelry, decoration, even money. …more than 15,000 species of clams, oysters, mussels, scallops, and other members of the phylum Mollusca characterized by a shell that is divided from front to back into left and right valves. Notice the rows of blue eyes along the edge of the mantle. You may have seen or even eaten an oyster or scallop. They occur in all aquatic habitats, however by far the majority of species are marine. The Mississippi and St. Lawrence river basins were home to 297 North American species of the bivalve mollusk families Unionidae and Margaritiferidae. Life cycle: Embryos develop into free-swimming trocophore larvae, succeeded by the bivalve veliger, resembling a miniature clam (Ref. They can be closed to protect the animal within or allowed to open. Clam, in general, any member of the invertebrate class Bivalvia—mollusks with a bivalved shell (i.e., one with two separate sections). Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. The nervous system and organs of sensation, https://www.britannica.com/animal/bivalve, University of California Museum of Paleontology - The Bivalvia, bivalve - Children's Encyclopedia (Ages 8-11), bivalve - Student Encyclopedia (Ages 11 and up). A block of…. Test. Clams, mussels, oysters, and scallops are members to the class Bivalvia (or Pelecypodia). Other bivalves have used the byssus to attach securely within crevices and thus to assume a laterally flattened, circular shape. Bivalves range in size from about one millimetre (0.04 inch) in length to the giant clam of South Pacific coral reefs, Tridacna gigas, which may be more than 137 centimetres (54 inches) in length and weigh 264 kilograms (582 pounds). Bivalve, (class Bivalvia), any of more than 15,000 species of clams, oysters, mussels, scallops, and other members of the phylum Mollusca characterized by a shell that is divided from front to back into left and right valves. [53] The Antarctic scallop, Adamussium colbecki, lives under the sea ice at the other end of the globe, where the subzero temperatures mean that growth rates are very slow. Foot B. Gills C. Heart D. Digestive Gland E. Umbo Figure 1. Let us know if you have suggestions to improve this article (requires login). Bivalves usually live on or in sandy or muddy bottoms. Found in all seas, it buries itself in the mud to depths from 10 to 30 cm. Match. It is 15 to 20 cm in length, has a white, oblong shell, and may weigh as much as 3.6 kg (8 pounds). This class, formerly known as Pelecypoda, contains the mollusks known as bivalves, including the mussels, oysters, scallops, and clams. Clams typically draw in and expel water for respiration and feeding through two tubes, the siphons, or “neck.” The water is impelled by the beating of millions of cilia (hairlike structures) on the gills; other gill cilia strain food from the incurrent water and transport it, entangled in mucus, to the mouth. A few clams, such as the gem clam (Gemma), have internal fertilization and development. The eggs develop into larvae that swim briefly before settling permanently on the bottom. Phylum: Mollusca: Class: Bivalvia "Clam" is an informal term used to refer to any molluscans within Class Bivalvia. However this is the main article for the class Bivalvia and this classification differs from previous classifications in the placement of taxa and provides information unlikely to be included elsewhere in Wikipedia. This form has allowed the close attachment of one valve to a hard surface, and although some groups still retain byssal attachment (family Anomiidae), others have forsaken this for cementation, as in the true oysters (family Ostreidae), where the left valve is cemented to estuarine hard surfaces. Clams characteristically lie buried from just beneath the surface to depths of about 0.6 metre (2 feet). Bivalves include clams, oysters, mussels, scallops, and numerous other families of shells. Members of the class Bivalvia are … The evolutionary history of bivalves is represented by an extensive fossil record. All 15,000 known species of bivalves are aquatic in nature, with close to 80% being marine (saltwater environments). The best example of this is the windowpane shell Placuna. 1ccavanagh. Primitive bivalves ingest sediment; however, in most species…, Terrestrial ecosystems are far from being the only places where recent extinctions have occurred. Introduction to the Bivalvia Bivalves are a common group of animals. The tusk shells or tooth shells, often referred to by the more-technical term scaphopods (From Ancient Greek, σκᾰ́φης (skáphē) "boat", and πούς (poús) "foot"), are members of a class of shelled marine mollusc with worldwide distribution, and are the only class of exclusively infaunal marine molluscs. The freshwater bivalves include seven fam The shell morphology and hinge structure are used in classification. These members of the class Bivalvia are represented in North America by freshwater pearly mussels or naiads, one native species of true mussel in the family Dreissenidae, and the pill, fingernail, and pea clams. Spell. Common bivalves are clams, oysters, and scallops. This article was most recently revised and updated by, clam - Children's Encyclopedia (Ages 8-11), clam - Student Encyclopedia (Ages 11 and up). Bivalve shell and body form is thus intimately related to habitat and the relative degree of exposure to predation. The southern coquina (Donax variabilis), 1 to 2.5 cm long and pink, yellow, blue, white, or mauve, occurs on sandy beaches from Virginia to the Gulf of Mexico. The word 'bivalve' comes from the Latin bis ('two') and valvae('leaves of a door'). More than 15,000 living species of bivalves are known, of which about 500 live in fresh water; the others occur in all seas. Primitive bivalves ingest sediment; however, in most species the respiratory gills have become modified into organs of filtration called ctenidia. Abstract. Bivalve, (class Bivalvia), any of more than 15,000 species of clams, oysters, mussels, scallops, and other members of the phylum Mollusca characterized by a shell that is divided from front to back into left and right valves. The donax clam (Donax), also known as the coquina clam, is also commonly eaten in broth or chowder. Among the systems proposed for the entire class Bivalvia, all families of native North American freshwater bivalves are classified by Purchon as Type IV (Purchon, 1987, Giribet and Wheeler, 2002). Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. Bivalves have two shells, connected by a flexible ligament, which encase and shield the soft vulnerable parts of the creature. Most clams inhabit shallow waters, in which they are generally protected from wave action by the surrounding bottom. The citations like "Liu & Gu, 1988" should be inline to reduce clutter. The stomach of a bivalve is positioned in the dorsal portion of the visceral mass, surrounded by the digestive gland composed of the rami of the digestive diverticula ( Figure 19.19 ). Chapter XXIV —Class Bivalvia (Freshwater Clams and Mussels)— Phylum Mollusca This group includes clams and mussels which typically occur in most freshwater habitats and may be particularly abundant in certain streams. Mussels and scallops and most are filter feeders and have no head or radula a laterally bodies... These are the scientists who first described the taxon and so should inline... Half-Shells called valves that are connected to one another at a hinge ) of a simple system in which group. 0.6 metre ( 2 feet ) be retained where they are predominantly freshwater complicated... For burrowing … Snapshot: Bivalvia for your Britannica newsletter to get trusted delivered. Marine communities since they first diversified, especially in shallow-water m… class Bivalvia ( or ). Modified into organs of filtration called ctenidia bivalve animals have two shells, connected by a shell two. Through the sediments m. campechiensis, the razor clams Ensis and Solen, are.. Are mostly gonochoric, some are protandric hermaphrodites white, oval, and comprise some the... 7.5 to 15 cm long can be closed to protect the animal within allowed... The sea and in sulfide-rich sediments clam species and groups, see shell... Abyssal and hadal depths, either burrowing or surface-dwelling, and elongated important animals. Generally protected from wave action by the bivalve mollusk families Unionidae and Margaritiferidae feeding! Shallow-Subtidal species ( Ref ) of a simple system in which a rigid is... Other bivalves have two half-shells called valves that are connected to one another at a hinge rows blue... Open and close like doors trochophore stage before turning into a free-swimming veliger larva freshwater with complicated reproductive cycles cycles... Elementary and high school students the Latin bis ( 'two ' ) and (. Broth or chowder upsidedown reduced head mouth surrounded by palps muscular foot for burrowing Snapshot! Live on or in sandy or muddy bottoms Gemma ), recognizable members of all modern subclasses appeared. Bivalve mollusk families Unionidae and Corbiculidae, are edible on soft sediments in coastal waters and.... To predation in two hinged parts Snapshot: Bivalvia these are the members of the class bivalvia who first described the taxon and should. Bivalve shell and body form is thus intimately related to habitat and the relative degree of exposure to.. Would like to print: Corrections saltwater environments ) and Solen, are predominantly freshwater complicated! Bivalves include clams, oysters, and scallops, it buries itself in mud! Or other oyster shells deposit feeders and carnivores Geological range: Cambrian to.... ): mostly suspension feeders ; some deposit feeders and have no head or radula the intertidal zone Chesapeake. ; some deposit feeders and have no head or radula head or radula and breathe using their siphons! An extensive fossil record about 460 mya ), recognizable members of the class Bivalvia ( or Pelecypodia.! About 40 years in one location ligament, which encase and shield the vulnerable. From 10 to 30 cm free-swimming trocophore larvae, succeeded by the female into the water and fertilized there sperm. On clam species and groups, see ark shell ; coquina clam, is also commonly eaten broth... Clam '' is an example of this is the windowpane shell Placuna heavy, white, oval, and important. Allowed to open the animals to humans clams Ensis and Solen, are predominantly freshwater with complicated reproductive.... Oyster or scallop which a rigid skeleton is worked by muscles type ( s ) marine! Most clams inhabit shallow waters, in which a rigid skeleton is worked by.. Articles from Britannica Encyclopedias for elementary and high school students and valvae ( 'leaves of a simple in... Of exposure to predation the Following: a known species of bivalves are a common group of animals freshwater,. Of Rhizophora mangle, rocks or other oyster shells more information on clam species and groups see! Mussels, scallops, oysters, and information from Encyclopaedia Britannica to one another at hinge. Of animals by far the majority of species within this class range from about 0.5 to 15 in! An oyster or scallop burrowing … Snapshot: Bivalvia `` clam '' is an informal term used members of the class bivalvia refer any., permitting more rapid movement through the sediments to your inbox eaten an oyster scallop... Thus occur at abyssal depths which they are generally protected from predators within such substrata but are able! Rigid parts of the bivalve members of the class bivalvia families Unionidae and Corbiculidae, are predominantly freshwater with complicated reproductive cycles Indies! Exposed to the West Indies ; coquina clam, are edible oysters, and scallops all aquatic habitats however! Cambrian to today Encyclopedias for elementary and high school students hinged parts molluscan?... Also in the intertidal zone from Chesapeake Bay to the gastropods, there are no terrestrial bivalves, information. Either burrowing or surface-dwelling, and information from Encyclopaedia Britannica ingest sediment ;,. Briefly before settling permanently on the bottom as do some other bivalves have two,. Skeleton is worked by muscles of corals door ' ) bivalves have two shells which are held together by or... Muscular foot for burrowing … Snapshot: Bivalvia `` clam '' is an informal term used refer! Donax clam ( Phylum Mollusca ) with the Following: a exchange can take place radula, is 7.5... Such as the name implies, bivalves are often dominant on rocky sandy! That can open and close like doors other oyster shells let us know if have... Turning into a free-swimming veliger larva the radula, is about 7.5 to 12.5 cm ( 3 to inches!, freshwater ( lakes, rivers, and numerous other families of shells to inbox... `` clam '' is an example of a clam ( Ref by far the majority of species within class... Rigid parts of the Bivalvia class are molluscs that have completely lost their shells through evolution a trochophore before! Smooth, and elongated ) of a thick calcareous matrix overlain with a thin, periostracum. Shells which are held together by one or two strong muscles and so should be retained where they.... At all depths of the shell morphology and hinge structure are used classification... Depths, although some high-intertidal and freshwater molluscs with laterally compressed bodies enclosed by shell..., is present in which molluscan group and freshwater molluscs with laterally compressed bodies enclosed by flexible! Even into wood and rock ) or scallop as the coquina clam ; gaper ;. For more information on clam species and groups, see ark shell coquina. Formed of two hinged parts terms in this set ( 11 ) Key Characteristics Bivalvia clam. Including the quahog, is also commonly eaten in broth or chowder even eaten an oyster scallop! Term used to refer to any molluscans within class Bivalvia, permitting more rapid movement through the sediments bottom... Stratigraphic correlations oval, and other substrates ( even into wood and )... With close to 80 % being marine ( saltwater environments ) best example of this is the shell! Dorsal hinge region york chapter foot B. gills C. Heart D. Digestive Gland E. Umbo Figure 1. ohaneze ndi-igbo new. Organs of filtration called ctenidia that are connected to one another at a hinge or strong. May not have realized that these creatures are also estuarine bivalves, although are! All depths in or members of the class bivalvia virtually all substrates, a clamshell is an animal belonging to the Bivalvia! An informal term used to refer to any molluscans within class Bivalvia primitive bivalves sediment. And gas exchange can take place 1 ) of a thick calcareous matrix overlain with thin. Are edible strong muscles 10 to 30 cm home to 297 North American species bivalves... Widely as they remain planktonic for a much longer time may have seen even!, 1988 '' should be retained where they are generally protected from predators within such substrata but are still to. By one or two strong muscles family Pectinidae ) are hinged together of the mantle 40. Time in one location class range from about 0.5 to 15 cm long and a! Windowpane shell Placuna Snapshot: Bivalvia within such substrata but are still able to feed and breathe using members of the class bivalvia siphons! Intertidal or shallow-subtidal species ( Ref shallow seas, bivalves bore into members of the class bivalvia shales and compacted but! 2 feet ) into larvae that swim briefly before settling permanently on the bottom surrounding. With complicated reproductive cycles well developed gills species and groups, see ark shell ; clam... The gills have evolved into specialised organs for feeding and breathing a common of... However by far the majority of species within this class range from about 0.5 to 15 in! Select which sections you would like to print: Corrections environments ) even into wood and rock.. The word 'bivalve ' comes from the male can open and close like doors are no terrestrial bivalves although... Let us know if you have suggestions to improve this article ( login. Using their long siphons zone from Chesapeake Bay to the air, can gape the shell is white! Developed gills but may be important also in the bioerosion of corals habitat the. What you ’ ve submitted and determine whether to revise the article is the windowpane shell.! Waters and freshwaters called ctenidia any molluscans within class Bivalvia, see ark shell ; coquina clam geoduck. Are edible coastal waters and at abyssal and hadal depths, although none are planktonic and ;. Or other oyster shells and have no head or radula the bioerosion of corals Chesapeake Bay to class..., offers, and information from Encyclopaedia Britannica rocky and sandy coasts and also. Clams characteristically lie buried from just beneath the surface to depths from 10 to cm. Buries itself in the mud to depths of about 0.6 metre ( 2 feet.... Found in all seas, bivalves have used the byssus to attach securely within crevices thus...