Placodermi

Placodermi is an extinct, paraphyletic class of armoured prehistoric fish, known from fossils, which lived from the late Silurian to the end of the Devonian Period. Their head and thorax were covered by articulated armoured plates and the rest of the body was scaled or naked, depending on the species. Placoderms were among the first jawed fish; their jaws likely evolved from the first of their gill arches. A 380-million-year-old fossil of one species represents the oldest known example of live birth For more information visit the Wikipedia Entry Get back to Fishes
Bothriolepis	Dunkleosteus	Groenlandaspis
Mcnamaraspis	Rolfosteus