''Unionicola'' is a genus of freshwater

arachnids Arachnida () is a Class (biology), class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, opiliones, harvestmen, Solifugae, came ...

, belonging to the family Unionicolidae. The genus was described in 1842 by

Samuel Stehman Haldeman Samuel Stehman Haldeman (August 12, 1812 – September 10, 1880) was an American naturalist and philologist. During a long and varied career he studied, published, and lectured on geology, conchology, entomology and philology. He once confided, ...

. The genus has

cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The ext ...

. Most ''Unionicola'' are associated with mollusks, but '' Unionicola crassipes'' and '' Unionicola minor'' are associated with sponges of family

Spongillidae Spongilidae is a family of sponges that live in freshwater lakes and rivers. The following genera are recognized in the family: * ''Anheteromeyenia'' Schröder, 1927 * ''Corvoheteromeyenia'' Ezcurra de Drago, 1979 * ''Corvospongilla'' Annandale, ...

. The association with mussels can be described as symbiotic. There is evidence that mites consume host tissue and can be associated with reduced host fitness, although the causal direction of the latter remains unclear. Species include the following: * '' Unionicola gracilipalpis'' * '' Unionicola figuralis'' * '' Unionicola crassipes'' * '' Unionicola aculeata'' * '' Unionicola ypsilophora'' (Bonz, 1783)

References

{{Taxonbar, from=Q4645080 Trombidiformes Acari genera Taxa named by Samuel Stehman Haldeman