Planodonta

Planodonta is a genus of freshwater mussels, also known as naiads or unionid mussels. These bivalve mollusks belong to the family Unionidae, which is the largest family of freshwater mussels. Planodonta mussels are typically found in the freshwater rivers and streams of North America, with a particular focus on the southeastern United States. They are characterized by their relatively flattened shells, which give the genus its name, derived from Greek words meaning "flat tooth."

The life cycle of Planodonta, like other freshwater mussels, is complex and involves a parasitic larval stage. The larvae, called glochidia, attach to the gills of fish, where they develop into juvenile mussels. This relationship is crucial for the dispersal of the mussel species. Adult Planodonta mussels are filter feeders, drawing water into their shells and extracting organic matter and small organisms. They play an important role in aquatic ecosystems by filtering water and serving as a food source for various animals.

Several species are recognized within the genus Planodonta, though taxonomic classifications can sometimes vary. These species often inhabit specific substrates, such as sand or gravel, within their riverine habitats. Like many freshwater mussel populations, Planodonta species can be vulnerable to habitat degradation, pollution, and the introduction of invasive species, making their conservation a concern for aquatic biologists.