Angarichthys hyperboreus is an extinct homostiid arthrodire placoderm from the Middle Devonian (either upper Eifelian or lower Givetian) of Siberia. It is known from an infragnathal plate, an intero-lateral plate, and a marginal plate found from the Middle Devonian strata of the Tynep Series formation, near the Bakhta River. A. hyperboreus differs from Homosteus in that the former's marginal plate has a ridge where the central plate would have overlapped it, and in the infragnathal, which is curved sigmoidally, and bears at least seven tooth-like prongs nearer to the functional anterior end (the plate, which is fragmentary, suggests that the intact plate would have born several more).