On the Orbit of Theropod Dinosaurs.

Primitively, theropod orbits are roughly circular in outline and this pattern is retained in most theropods. Large-headed theropods show a much greater diversity in the shape of the orbit, ranging from strongly elliptical to keyhole shaped, to a near complete division of the orbit at mid-height by projections of the postorbital, Iacrimal, or both. Orbit shape is not congruent with current theropod…