Unionida
Sign in to saveUnionida is a monophyletic order of freshwater mussels, aquatic bivalve molluscs. The order includes most of the larger freshwater mussels, including the freshwater pearl mussels. The most common families are the Unionidae and the Margaritiferidae. All have in common a larval stage that is temporarily parasitic on fish, nacreous shells, high in organic matter, that may crack upon drying out, and siphons too short to permit the animal to live deeply buried in sediment.
Article
12 sectionsContents
- Morphology
- Evolutionary history
- Distribution
- Life habits
- Reproduction
- Conservation issues and endangered species status
- Commercial significance
- Freshwater pearl industry
- Button manufacturing industry
- Taxonomy
- References
- External links
Unionida is a monophyletic order of freshwater mussels, aquatic bivalve molluscs. The order includes most of the larger freshwater mussels, including the freshwater pearl mussels. The most common families are the Unionidae and the Margaritiferidae. All have in common a larval stage that is temporarily parasitic on fish, nacreous shells, high in organic matter, that may crack upon drying out, and siphons too short to permit the animal to live deeply buried in sediment.
==Morphology== The shells of these mussels are variable in shape, but usually equivalve and elongate. They have solid, nacreous valves with a pearly interior, radial sculpture, and an entire pallial line. left|thumb|Freshwater mussel showing glossary of terms. center|thumb|300px|Several species of freshwater pearl mussels collected in a river during a survey of the Marais des Cygnes National Wildlife Refuge.