Bivalvia
Sign in to savethumb|alt=Shell of the giant clam (Tridacna gigas)|Empty shell of the giant clam (Tridacna gigas) thumb|alt=Sword razor|Empty shells of the Ensis ensis|sword razor (Ensis ensis) Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consisting of a hinged pair of half-shells known as valves. As a group, bivalves have no head and lack some typical molluscan organs such as the radula and the odontophore. Their gills hav
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Bivalves are aquatic molluscs with soft bodies enclosed in a pair of hinged, hard shells called valves, and they include familiar creatures like clams and mussels found in both ocean and freshwater environments. These animals lack a head and some organs that other molluscs possess, making them structurally distinct within their larger group.
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Article
35 sectionsContents
- Etymology
- Anatomy
- Mantle and shell
- Muscles and ligaments
- Nervous system
- Senses
- Circulation and respiration
- Digestive system
- Modes of feeding
- Digestive tract
- Excretory system
- Reproduction and development
- Comparison with brachiopods
- Evolutionary history
- Diversity of extant bivalves
- Distribution
- Behaviour
- Predators and defence
- Mariculture
- Use as food
- Viral and bacterial infections
- Paralytic shellfish poisoning
- Amnesic shellfish poisoning
- Ecosystem services
- Other uses
- Pearls and mother-of-pearl
- Symbolism
- Bivalvian taxonomies
- Practical taxonomy of R.C. Moore
- 1935 taxonomy
- Taxonomy based upon hinge tooth morphology
- Taxonomy based upon gill morphology
- 2010 taxonomy
- References
- Further reading
thumb|alt=Shell of the giant clam (Tridacna gigas)|Empty shell of the giant clam (Tridacna gigas) thumb|alt=Sword razor|Empty shells of the Ensis ensis|sword razor (Ensis ensis) Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consisting of a hinged pair of half-shells known as valves. As a group, bivalves have no head and lack some typical molluscan organs such as the radula and the odontophore. Their gills have evolved into ctenidia, specialised organs for feeding and breathing.
Common bivalves include clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. Majority of the class are benthic filter feeders that 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 scallops and file shells, can swim. Shipworms bore into wood, clay, or stone and live inside these substances.