Fig. 1 in Scapular orientation in theropods and basal birds, and the origin of flapping flight

Fig. 1. Scapular position and glenoid orientation in articulated skeletons of non−avian dinosaurs, with glenoids indicated by arrows. A. Dorsal view of the ornithischian dinosaur Psittacosaurus mongoliensis, AMNH 6254, showing lateral position and wide spacing of scapulae. B. Lateral view of the ornithischian dinosaur Centrosaurus apertus, AMNH 5351, showing ventral orientation of glenoid and position of glenoid anteroventral to ribcage. C. Lateral view of the ornithomimid theropod dinosaur Struthiomimus altus, AMNH 5339, showing position of glenoid anteroventral to ribcage. D. The deinonychosaurian theropod dinosaur Velociraptor mongoliensis, IGM 100/976, in dorsal (D1), right lateral (D2), and anterior (D3) views, with the furcula outlined in white for clarity, showing that the scapulae are widely spaced, laterally positioned, and exhibit ventrally oriented glenoids, as in other dinosaurs. Broken white lines in (D1) indicate lateral extemities of vertebral column.