Ateleaspis

Ateleaspis is an extinct genus of primitive ostracoderm fish that lived in the Early Silurian to Early Devonian periods. Like other ostracoderms, Ateleaspis had a head shield similar to that of Cephalaspis. Species from Silurian period were found in Norway and Scotland, but now has been found also in Siberia from Early Devonian period.

Description
Ateleaspis possibly is the most basal vertebrate with paired fins. Ateleaspis was a small fish (about 15 - 20 cm) and had a flat headshield a narrow trunk covered by brick-like scales.