Figure 4 in Dromaeosaurid crania demonstrate the progressive loss of facial pneumaticity in coelurosaurian dinosaurs

Figure 4. Reconstruction of the antorbital sinus in coelurosaurs. The second sentence in the figure caption should read: Skulls of (A) Velociraptor, (B) Tsaagan, (C) Tyrannosaurus, (D) Deinonychus, (E) Saurornithoides, and (F) Khaan. Antorbital sinus in blue, with location of the maxillary fenestra in black and promaxillary fenestra in yellow. Photo of Deinonychus courtesy of the Division of Vertebrate Paleontology, Peabody Museum of Natural History.