Five new mussel species discovered in Southeastern U.S. rivers

Researchers have identified five previously unknown species of freshwater mussels in river basins across the Southeastern United States, including Missouri, Arkansas, Mississippi, Alabama, Louisiana, and Texas. The discovery, published in the journal Zootaxa, was made possible through DNA sequencing after scientists realized that many specimens previously thought to be common species were actually distinct genetic lineages.

Freshwater mussels play a critical role in filtering and cleaning river water, yet they are among the most imperiled groups of animals in North America. A 2026 conservation review indicates that more than two-thirds of the continent's approximately 300 native freshwater-mussel species are considered at risk.

The study, involving scientists from the Shedd Aquarium, Arkansas State University, and the U.S. Geological Survey, highlights the importance of accurate taxonomy. Because many species look nearly identical or change shell shape based on their environment, genetic testing was necessary to distinguish them. Some of the newly identified species are rare and confined to single river basins, making them highly vulnerable to local extinction.