Armored Fish Fossil (Placoderm)Placoderm, were a group of primitive jawed fishes known only from fossil remains. They existed throughout the Devonian Period (about 416 million to 359 million years ago), with two species continuing their existence into the later Carboniferous Period. During the Devonian Placoderms they were a dominant group, living in freshwater sediments of every continent except South America. Although most placoderms were small in size, some actually grew over 13