Placoderms are an extinct group of jawed fishes with bony armour covering their head and neck region. Dunkleosteus was the largest placoderm and the top predator during the late Devonian. It could grow up to 10 metres long and weigh as much as three elephants. pic.twitter.com/Ne8WbmGJQ9
— Royal Tyrrell Museum of Palaeontology (@RoyalTyrrell) October 16, 2019