Paddlefish (family Polyodontidae) are basal Chondrostean ray-finned fish. They have been referred to as "primitive fish" because they have evolved with few morphological changes since the earliest fossil records of the Late Cretaceous, seventy to seventy-five million years ago.  Polyodontids are exclusively North American with the exception of the genus Psephurus, which includes solely the Chinese paddlefish (Psephurus gladius).