Fig. 7 in Quadrupedal dinosaurs did not evolve fully pronated forearms: New evidence from the ulna

Fig. 7. Comparison of true standardized views of semi-pronated forearms in a representative sample of extant, nontherian tetrapods, in flexor (A1–F1) and distal (A2–F2) views. A. An allogatorid crocodilian, Alligator mississippiensis (Daudin, 1802) (FMNH 284695). B. A ratite bird, Struthio camelus Linnaeus, 1758 (FMNH 489294). C. A monitor lizard, Varanus komodoensis Ouwens, 1912 (FMNH 22197). D. A salamander, Ambystoma tigrinum (Green, 1825) FMNH 22010). E. A semi-aquatic turtle Apalone spinifera (Lesueur, 1827) (HDW NIU 1086), reversed. F. A more terrestrial turtle, Chrysemys picta (Schnei- der, 1783) (INHS 23894). Reversed specimens in this and following figures refer to elements from the right sides that have been digitally flipped. Note that in E the radius and ulna are fused in the morphology shown, and that the humerus may not be rotated far enough to the left. Note also that, in vivo, articular cartilage and, in some cases wrist bones (e.g., intermedium), may separate the distal radial and ulnar epiphyses beyond what is pictured here for specimens C and F. Not to scale.