1) Duckbill 2) Fish 3) Ganoid 4) Ganoid fish 5) Polyodon spathula 
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 th.....
• (n.) A large ganoid fish (Polyodon spathula) found in the rivers of the Mississippi Valley. It has a long spatula-shaped snout. Called also duck-billed cat, and spoonbill sturgeon.
either of two species of archaic freshwater fish with a paddle-like snout, wide mouth, smooth skin, and cartilaginous skeleton. A relative of the ... [1 related articles]
Pad'dle·fish` noun (Zoöl) A large ganoid fish ( Polyodon spathula ) found in the rivers of the Mississippi Valley. It has a long spatula-shaped snout. Called also duck-billed cat , and spoonbill sturgeon . 
The paddlefish (Polyodon spathula) or duck-billed cat, spoonbill sturgeon, is a large American ganoid fish found in the rivers of the Mississippi Valley. It has a long spatula-shaped snout.
[n] - primitive fish of the Mississippi valley having a long paddle-shaped snout
duckbill 2 Polyodon spathula noun primitive fish of the Mississippi valley having a long paddle-shaped snout