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Freshwater bivalves are molluscs of the order Bivalvia that inhabit freshwater ecosystems. They are one of the two main groups of freshwater molluscs , along with freshwater snails . The majority of bivalve molluscs are saltwater species that live in the marine habitats , but a number of families have evolved to live in fresh water (and in some ...
Bivalvia (/ b aɪ ˈ v æ l v i ə /) 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.
Velesunio wilsonii come from one of two classes of molluscs that have successfully inhabited freshwater ecosystems. [1] All other mollusc classes remain in marine ecosystems. [1] Bivalve molluscs evolved in marine ecosystems before slowly moving into estuaries and inhabiting upstream freshwater habitats, evolving to tolerate lower salinity ...
The two major classes of molluscs have representatives in freshwater: the gastropods (snails) and the bivalves (freshwater mussels and clams.) It appears that the other classes within the Phylum Mollusca -the cephalopods, scaphopods, polyplacophorans, etc. - never made the transition from a fully marine environment to a freshwater environment.
Murphy, Richard C. 1971. The structure and ultrastructure of the pineal organ of the bluefin tuna, Thunnus thynnus. J. Morph. 133(1):1-16. Murphy, Richard C. 1983. The introduced bivalve, Mercenaria mercenaria in a shallow coastal ecosystem: 1) Factors affecting its distribution, 2) Contribution to benthic community metabolism. Ph.D. Dissertation.
One bivalve group, the rudists, became major reef-builders in the Cretaceous, but became extinct in the Cretaceous–Paleogene extinction event. [26] Even so, bivalves remain abundant and diverse. The Hyolitha are a class of extinct animals with a shell and operculum that may be molluscs.
Unionidae burrow into the substrate, with their posterior margins exposed. They pump water through the incurrent aperture, obtaining oxygen and food. They remove phytoplankton and zooplankton, as well as suspended bacteria, fungal spores, and dissolved organic matter.
A marine coastal ecosystem is a marine ecosystem which occurs where the land meets the ocean. Worldwide there is about 620,000 kilometres (390,000 mi) of coastline. Coastal habitats extend to the margins of the continental shelves, occupying about 7 percent of the ocean surface area.