Paramylostoma arcualis is an extinct selenosteid arthrodire placoderm from the Late Famennian Cleveland Shale of Late Devonian Ohio. It has a compressed, box-like head and thoracic armor, and large, rounded orbits. However, in comparison with other selenosteids, such as Selenosteus, P. arcualis' orbits were rather small. P. arcualis had smooth jaws that suggest the animal was durophagous.
- ^ Denison, Robert (1978). Handbook of Paleoichthyology, Volume 2, Placodermi. New York: Gustav Fischer Verlage. p. 97. ISBN 9780895740274.