Unionoida
From Wikipedia, the free encyclopedia
| Unionoida | |
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| A live individual of Anodonta anatina | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Subclass: | Palaeoheterodonta |
| Order: | Unionoida Stoliczka, 1871 |
| Families | |
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Unionoida is an order of freshwater mussels, aquatic bivalve mollusks. The order includes most of the larger freshwater mussels, including the freshwater pearl mussels. 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.
Families, genera, and species are found on six continents, where they are restricted exclusively to freshwater. Many face conservation issues due to habitat degradation or over-exploitation for their shell. There are approximately 900 species worldwide.
[edit] Families in the Order Unionoida
- Etheriidae Swainson, 1840
- Margaritiferidae Haas, 1940
- Mutelidae Swainson, 1840
- Unionidae Fleming, 1828
- Hyriidae Swainson, 1840
- Mycetopodidae Gray, 1840
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