Dunkleosteus

Dunkleosteus was a prehistoric arthrodire. It was a primitive fish from the later Devonian period, about 360 million years ago. "Dunkleosteus" was a heavily armoured placoderm. Fossils have been found in Morocco, Africa, Poland, Belgium, China, and the USA.
Placodermi first appeared in the Silurian, and the group became extinct during the transition from the Devonian to the Carboniferous, leaving no descendants. The class lasted barely 50 million years, in comparison to the 400 million year long history of sharks.
Description.
This top predator was up to 11.5 ft (3.5 m) long and had large, scissor-like cutting jaws with serrated, razor-sharp bones, but no teeth. Its skull was over 2 feet (65 cm) long. It had a jointed neck, an eel-like tail, a scale-less body, and hinged body shields.