Family of gastropods
Viviparidae, sometimes known as the river snails or mystery snails, are a family of large aquatic gastropod mollusks, being some of the most widely distributed operculate freshwater snails.
This family is classified in the informal group Architaenioglossa according to the taxonomy of the Gastropoda by Bouchet &amp; Rocroi, 2005.
Distribution.
This family occurs nearly worldwide in temperate and tropical regions, with the exception that they are absent from South America.
There are two genera of Viviparidae in Africa: "Bellamya" and "Neothauma".
The oldest known vivparid is "Viviparus langtonensis" from the Middle Jurassic of England. The oldest records from the Southern Hemisphere is from the Late Jurassic Talbragar fossil beds of Australia.
Taxonomy.
The family Viviparidae contains 3 subfamilies (according to the taxonomy of the Gastropoda by Bouchet &amp; Rocroi, 2005):
Genera.
Genera within the family Viviparidae include:
subfamily Viviparinae Gray, 1847
subfamily Bellamyinae 
subfamily Lioplacinae 
subfamily ?
Life cycle.
Life spans have been reported from 3 to 11 years in various species of Viviparidae.
References.
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