Reconstruction of anteroposterior movement of the mandible during the chewing stroke in Infernogallus jamesi. Three-dimensional models of the skull and mandible showing potential mandible positions based on contact of the articular and quadrate, and resulting adductor musculature orientations. From rest (a), contraction of the m. depressor mandibulae would open the mouth (b). Contraction of the the mm. pterygoideus in this position would move the mandible forwards (c). This anterior movement would increase the anteroposterior orientations of the temporal adductor musculature (see also Supplementary Fig. 7a–c). Contraction of the temporal adductor muscles in this position would bring the mandible upwards and backwards (c). This movement would enable manipulation and compression of foods between the triturating features of the dentary and the maxillovomeral process of the palate (d). Blue arrows and text indicate inferred motions, black text indicates muscle groups contracting. M depressor mandibulae could not be reconstructed based on the areas exposed in ROM VP 65050, but it has deeply conserved attachments on the posterior process of the squamosal and retroarticular process of the mandible in archosaurs 5 . In positions (c, d), the m depressor mandibulae would rest medial to the quadratojugal.