Polyodontiformes

Polyodontiformes is an order of ray-finned fish that includes only two extant species, the American paddlefish (Polyodon spathula) and the Chinese paddlefish (Psephurus gladius). Both species are characterized by their elongated, paddle-shaped rostrum, which is covered in sensory pores believed to detect electroreception. These fish are large, filter feeders, primarily consuming zooplankton.

The American paddlefish is found in the Mississippi River basin of North America, while the Chinese paddlefish was historically found in the Yangtze River of China. Sadly, the Chinese paddlefish is now believed to be extinct, with the last confirmed sighting in 2003. The American paddlefish is considered a vulnerable species due to habitat loss, dam construction, and overfishing.

Fossil evidence suggests that polyodontiformes were once more diverse and widespread. The earliest fossils attributed to this order date back to the Cretaceous period. Historically, the order contained more families and genera, but over time, diversification led to the current depauperate state. The remaining members of Polyodontiformes are important components of their respective ecosystems, playing a role in nutrient cycling through their feeding habits. Conservation efforts are underway to protect the American paddlefish and its habitat.