Bivalvia
Bivalvia is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a hinged pair of half-shells known as valves.
About Bivalvia
Bivalvia is the second largest class of mollusks, with over 9,200 species. Shells range in size from from less than 1mm to 1,600mm. The heaviest shelled mollusc is the Giant Clam (Tridacna gigas) that can attain a weight of over 300kg. Popular families with shell collectors are Pectenidae (Scallops) and Spondylidae (Spiney oysters). Certain species of “giant” clams are protected by International law (CITES) and their shells may not be exported/imported.
Common bivalves include clams, oysters, cockles, mussels and scallops.
Bivalves also include shipworms that bore into wood, clay, or stone and live inside these substances.
Bivalves appear in the fossil record first in the early Cambrian more than 500 million years ago.