Paddlefishes

Paddlefish are members of the ray-finned fish family Polyodontidae, which belong to the basal order Acipenseriformes, one of two living groups within this order alongside sturgeons (Acipenseridae). Their most distinctive feature is an elongated rostrum that enhances electroreception, allowing them to detect prey in murky water. Both recent and fossil paddlefish occur exclusively in North America and Eastern Asia.

Eight species are known, six of which are prehistoric and only known from fossils—five from North America and one from China. Of the two species to have survived until modern times, the American paddlefish (Polyodon spathula) inhabits the Mississippi River basin in the United States, while the now extinct Chinese paddlefish (Psephurus gladius, also known as the "Chinese swordfish") inhabited the Yangtze and Yellow River basins in China. The earliest known paddlefish fossil, Protopsephurus, dates to approximately 120 million years ago during the Early Cretaceous epoch in China.