Jamoytius was a jawless fish that lived during the Silurian period. It was a distant relative of modern-day lamprey.
Jamoytius was probably a filter-feeder or a detrius-feeder. The fish had a cartilaginous skeleton, and a branchial basket resembling the cyclostomes - used to suggest that it was a near-ancestor to that clade. It is also the earliest known vertebrate with camera-type eyes. It also possessed weakly mineralised scales.