Placoderm

Placoderm means plate-skinned in Greek.

They had bony armor plates covering their heads and upper bodies.

Placoderms were the first vertebrates to evolve jaws, and they were the dominant fish of the Devonian.

Their jaws had no teeth, but they had tooth-like structures that extended into the mouth, a continuation of the bony plates on the head.

Most placoderms were predators.