''Rotundaria tuberculata'', commonly called the purple wartyback, is a

freshwater mussel Freshwater bivalves are molluscs of the order Bivalvia that inhabit freshwater ecosystems. They are one of the two main groups of freshwater molluscs, along with freshwater snails. The majority of bivalve molluscs are saltwater species that l ...

, an aquatic

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

. This species is native to eastern North America, generally in the

Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...

drainage, where it is wide-ranging. It is still common in many areas, particularly in the southern part of its range, but is being negatively impacted by

water pollution Water pollution (or aquatic pollution) is the contamination of Body of water, water bodies, with a negative impact on their uses. It is usually a result of human activities. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and ...

and channelization. In the Mississippi River drainage, it is threatened by overgrowth of invasive

zebra mussel The zebra mussel (''Dreissena polymorpha'') is a small freshwater mussel, an Aquatic animal, aquatic bivalve mollusk in the family Dreissenidae. The species originates from the lakes of southern Russia and Ukraine, but has been accidentally Intro ...

s (''Dreissena polymorpha'') and, in Canada, by predation on juvenile mussels and possibly unsuccessful development of larval

glochidia The glochidium (plural glochidia) is a microscopic larval stage of some freshwater mussels, aquatic bivalve mollusks in the families Unionidae and Margaritiferidae, the river mussels and European freshwater pearl mussels. These larvae are t ...

on the invasive

round goby The round goby (''Neogobius melanostomus'') is a euryhaline bottom-dwelling species of fish of the family (biology), family Gobiidae. It is native to Central Eurasia, including the Black Sea and the Caspian Sea. Round gobies have established larg ...

(''Neogobius melanostomus''). It was formerly classified as the sole species in the genus '' Cyclonaias'', but in 2012 it was moved to ''Rotundaria'' based on genetic evidence.

References

Molluscs of the United States tuberculata Bivalves described in 1820 Taxa named by Constantine Samuel Rafinesque {{Unionidae-stub