Unionidae is a family of freshwater mussels, found world-wide living buried in mud, silt or sand in rivers, streams and lakes. The shell is equivalve, nacreous and with a thick periostracum. The hinge mostly with two cardinals and two posterior lamellar teeth. In biological classification, family (Latin: familia, plural familiae) is 1) a rank or 2) a taxon in that rank. ... Subclasses Pteriomorpha (marine mussels) Palaeoheterodonta (freshwater mussels) Heterodonta (zebra mussels) The term mussel is used for several families of bivalve mollusks inhabiting lakes, rivers, and creeks, as well as intertidal areas along coastlines worldwide. ... The English word POSTERIOR is identical to the original Latin adjective, and has two different uses : as an ADJECTIVE, it indicates that someone or something is behind another, either spatially or chronologically it also became a SUBSTANTIVE, indicating the rear-end, especially of a person, i. ...

All Unionidae live half-buried in the sediment, their siphons sticking out. They pump water throught the inflow and outflow siphons, obtaining oxygen and food. Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of water or other liquid. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ...

Unionidae have a remarkably complex life history. All Unios are of separate sex. The sperm is excreted through the male’s outflow opening and ingested by the female through the inflow opening. Fertilized eggs move from the gonads to the gills (marsupia) where they further ripen and turn into the first larval stage, the glochidium. Mature glochidia are ejected 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 of as juvenile mussels which bury themselves in the sediment. The Guppy (Poecilia reticulata) is one of the most popular freshwater aquarium fish species in the world. ... Juvenile (left) and adult (right) leaves of Stone Pine A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. ... Mussels A mussel is a bivalve shellfish that can be found in lakes, rivers, creeks, intertidal areas, and throughout the ocean. ...

Genera and species

• Genus Alasmidonta
  • Dwarf wedgemussel, Alasmidonta heterodon, I Lea, 1830
• Genus Anodonta
  • Duck mussel, Anodonta anatina
  • Swan mussel, Anodonta cygnea
• Genus Cucumerunio Iredale, 1934
  • Cucumerunio websteri delli, McMichael & Hiscock, 1958
  • Cucumerunio websteri websteri, Simpson, 1902
• Genus Epioblasma
  • Northern Riffleshell, Epioblasma torulosa rangiana, (I Lea, 1838)
• Genus Hyridella Swainson, 1840
  • New Zealand freshwater mussel, Hyridella menziesi, Gray, 1843
• Genus Lampsilis
• Genus Lasmigona
• Genus Pseudanodonta
  • Depressed river mussel, Pseudanodonta complanata
• Genus Pyganadon
• Genus Strophitis
• Genus Unio
  • Thick shelled river mussel, Unio crassus Philipsson in Retzius, 1788
  • Painter's mussel, Unio pictorum
  • Swollen river mussel, Unio tumidus
• Genus Utterbackia

Subclasses Heterodonta Palaeoheterodonta A mussel is a bivalve mollusk that can be found in lakes, rivers, creeks, intertidal areas, and throughout the ocean. ...

References

• A B Powell, New Zealand Mollusca, (William Collins Publishers Ltd, Auckland, New Zealand 1979) ISBN 0-00-216906-1