Origin and evolution of ostracoderms

Ostracoderms were early jawless vertebrates that lived from the Cambrian to the late Devonian period. They were covered in bony plates and resembled modern hagfish and lampreys. While some evidence suggests they lived in freshwater, their habitat is still debated. Later in the Devonian, jawed fish evolved from ostracoderms and outcompeted them, contributing to their extinction by the end of the period. Ostracoderms were divided into two main groups and played an important role in the early evolution of vertebrates.