Postfrontal bone
The postfrontal is a paired cranial bone found in many tetrapods. It occupies an area of the skull roof between and behind the orbits, lateral to the frontal and parietal bones, and anterior to the postorbital bone.
The postfrontal forms part of the rear and upper border of the eye socket when present. It is particularly large in many extinct amphibians and their sarcopterygian ancestors, stretching forwards to contact the prefrontal, thus separating the frontal from the rim of the orbit. In living amphibians, the postfrontal is absent, having failed to ossify during development. The postfrontal is present but reduced in some reptiles, including modern squamates. It is lost or fused to surrounding bones in mammals, crocodylomorphs and dinosaurs, though it is present in other extinct archosaurs.