FIGURE 41 in A reappraisal of the cranial and mandibular osteology of the spinosaurid Irritator challengeri (Dinosauria: Theropoda)

FIGURE 41. Line drawings of the re-arranged and articulated skull of Irritator challengeri (SMNS 58022). A, completely closed lower jaw; B, laterally spreading and rotating lower jaw rami during depression; C, the maximum opening angle of around 40° (in wider angles, the raised posterolateral margin of the glenoid fossa hits the quadrate). The lower jaw rami spread approx. 8° sideways, producing a pharynx mediolaterally widened around 3 cm per side. Additionally, each lower jaw ramus is rotating around the long axis by approx. 2° (dorsally lateral and ventrally medial). These values are measured from the point of origin for the maximum opening angle in relation to the closed position.