The Devonian ancestors of fishes living today belonged to two main nonarmored groups. The cartilaginous fish, so-called because cartilage formed their skeletons, later gave rise to sharks and rays.

Vertebrates, including humans, trace their lineage back to ancient fish that lived more than 400 million years ago during the Devonian period ... was present when the ancestor of jawed and ...

We have arrived in the Devonian period ... can be traced back to a fish. This encompasses not only amphibians, reptiles and birds, but also mammals—humans included. Yet one mystery remains ...