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Unionidae: Wikis


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From Wikipedia, the free encyclopedia

The shell of a duck mussel, Anodonta anatina
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Subclass: Paleoheterodonta
Order: Unionoida
Family: Unionidae

See text for genera and species.

Unionidae is a family of freshwater mussels, the largest in the order Unionoida, the bivalve mollusks sometimes known as river mussels, naiads, or simply as unionids.

The range of distribution for this family is world-wide. It is at its most diverse in North America, with about 297 recognized taxa[1][2][3], but China and Southeast Asia also support very diverse faunas.

Freshwater mussels occupy a wide range of habitats, but most often occupy lotic waters.


Life habits

Unionidae burrow into the substrate, with their posterior margins exposed. They pump water through the incurrent aperture, obtaining oxygen and food.

Unionidae are distinguished by a unique and complex life cycle. Most Unionids are of separate sex (although some species, such as Elliptio complanata, are known to be hermaphroditic). The sperm is ejected from the mantle cavity through the male’s excurrent aperture and taken into the female's mantle cavity through the incurrent aperture. Fertilized eggs move from the gonads to the gills (marsupia) where they further ripen and metamorph into glochidia, the first larval stage. Mature glochidia are released by the female and then attach to the gills, fins or skin of a host fish. A cyst is quickly formed around the glochidia, and they stay on the fish for several weeks or months before they fall off as juvenile mussels which then bury themselves in the sediment.


Genera within the family Unionidae include:


  1. ^ Williams, J. D, M. L. Warren, K. S. Cummings, J. L. Harris, and R. J. Neves (1993). "Conservation Status of Freshwater Mussels of the United States and Canada". Fisheries 18 (9): 6–22. doi:10.1577/1548-8446(1993)018<0006:CSOFMO>2.0.CO;2.  
  2. ^ Burch, John B.. 1975. Freshwater unionacean clams (Mollusca: Pelecypoda) of North America. Biota of Freshwater Ecosystems, Identification Manual No. 11. U.S. Gov. Printing Office. 114p.
  3. ^ Heard, William H. 1979. Identification Manual of the Freshwater Clams of Florida. Fla. Dept. Environmental Regulation, Technical Series 4(2): 1-83.

External links


Up to date as of January 23, 2010

From Wikispecies


Main Page
Cladus: Eukaryota
Supergroup: Unikonta
Cladus: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Spiralia
Cladus: Lophotrochozoa
Phylum: Mollusca
Classis: Bivalvia
Subclassis: Paleoheterodonta
Ordo: Unionoida
Superfamily: Unionoidea
Familia: Unionidae
Genera: Alasmidonta - Cucumerunio - Epioblasma - Hyridella - Lasmigona - Lampsilis - Strophitus - Pyganodon - Quadrula - Unio - Utterbackia


Unionidae Fleming, 1828


Unionidae Report on ITIS

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