There are six known species: four extinct species known only from fossil remains (three from western North America, one from China), and two extant species, including the American paddlefish (Polyodon spathula) which is native to the Mississippi River basin in the U.S. and the critically endangered Chinese paddlefish (Psephurus glades) which is endemic to the Yangtze River Basin in China.[5] Chinese paddlefish are also commonly referred to as "Chinese swordfish", or "elephant fish".[6][7]