Basommatophoran

Basommatophoran is an informal grouping of freshwater and terrestrial snails within the class Gastropoda. They are characterized by having eyes located at the base of their tentacles, distinguishing them from their marine relatives, the stylommatophorans, which have eyes at the tips of their tentacles. Basommatophorans are a diverse group, inhabiting a wide range of aquatic environments, including ponds, lakes, rivers, and swamps, as well as damp terrestrial habitats. Many species are important components of freshwater ecosystems, serving as food sources for other animals and playing roles in nutrient cycling. Some basommatophorans are known to be intermediate hosts for parasitic flatworms, which can have significant impacts on human and animal health. Common examples include snails from the families Lymnaeidae (pond snails), Planorbidae (ramshorn snails), and Physidae (bladder snails). Their reproductive strategies vary, with some species being hermaphroditic. The classification of basommatophorans has undergone revisions, and the term is often used in a broader sense to encompass a polyphyletic assemblage of pulmonate gastropods.