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.