The oldest jawless fish with bone is known from 470 million years ago (Arandaspis). It is similar to the oldest complete fossil of Sacabamaspis from the Late Ordovician. The earliest Ordovician fish seem to be relatives (and perhaps ancestral to) the later group of heterostracans.

When did fish evolve?

Fish. The first fish appeared around 530 million years ago and then underwent a long period of evolution so that, today, they are by far the most diverse group of vertebrates.

When did Placoderms first evolve?

The first record of the jawed Placodermi is from the Early Devonian, about 400 million years ago.