1. 
   Helicoprion
   Helicoprion was an ancient fish from the Late Paleozoic (it appeared during the Carboniferous period, about 345 million years ago). This predatory fish is known only from fossilized teeth; it probably had a cartilaginous body (which does not fossilized well and is possibly why a fossil skeleton from...
   Found op http://www.enchantedlearning.com/subjects/dinosaurs/glossary/
   
   
2. 
   Helicoprion
   Helicoprion ("Spiral Saw") was a long-lived genus of shark-like cartilaginous fish that first arose in the oceans of the late Carboniferous {Ma|280}, survived the Permian-Triassic Extinction Event, and eventually went extinct during the early Triassic, {Ma|225}. The only fossils known are the teeth...
   Found op http://en.wikipedia.org/wiki/Helicoprion
   
   

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