placodermi

This is the head of the placodermi it is known as the earliest fish known with a jaw. They have heavy armor on the head and neck. It has an unusual joint in the dorsal armor between the head and the neck. This joint allows the head to move upward as the jaw moves downward ceating a larger gape. The rest of its body was either naked or covered with small scales. Placodermis did not have teeth. They were boney plates formed like teeth. Sometimes they were razor sharp litterally self-sharpening edges. In 1997 the first fossils of a placodermi were found in Antartica. They also had color vision they were very successful but they only lasted about 50 million years. Many of these taxa died out around the end of the Devonian Period for reasons that are still not well understood. Placoderms survived until the very end of the Devonian, and their extinction appears to have been quite sudden, but its causes are still unknown. Placodermi were also closley related to sharks.