Definitions for "Placoderm"
fishlike vertebrate with bony plates on head and upper body; dominant in seas and rivers during the Devonian; considered the earliest vertebrate with jaws
A type of early armored fish that was common in the Devonian Period of the
Placoderms (meaning "plated skin") were armored fish that evolved during the Silurian Period, about 420 million years ago. They diviersified and came to dominate the seas by the Devonian. They went extinct bout 355 million years ago. They had hinged bony armor on their head and thorax. They had no teeth, but did have bony reidges that acted like teeth. Some placoderms included Antiarchi, Bothriolepis, Dunkleosteus (the largest placoderm), Groenlandapsis, and Phyllolepis. Placoderms were early fish, but not sharks.
Keywords:  one
One of the Placodermi.