Dunkleosteus (From "(David) Dunkle" + osteus (οστεος, Greek: bone)) was one of the largest arthrodire placoderms. It lived during the late Devonian Period about 380–360 million years ago.
It was 10 metres (33 ft) long and weighted 3.6 tonnes (4.0 short tons) and was heavily armoured. Dunkleosteus was the top predator of its time.