Pteraspids were early agnathanvertebrates. They lived from later Silurian to the end of the Devonian. Fossils are found in Europe and North America.
The whole group has the head and front of the body armoured. Delicate, finger-like parts of the plates were at the edges of the mouth. This suggests they were filter feeders taking plankton from the water column.[1]
References
↑Purnell, Mark A. 2002. Feeding in extinct jawless heterostracan fishes and testing scenarios of early vertebrate evolution. Proceedings of the Royal Society of London B: Biological Sciences. 269 (1486) 83-88.[1]