Fig. 4: Ontogeny and paedomorphosis in sauropodomorph dinosaurs.

a Reconstructed embryonic skeleton of Lufengosaurus. b Thin section through two equally tall embryonic teeth in the wide alveolar trough showing two generations of teeth without evidence of replacement. c Reconstruction of adult Lufengosaurus, CVP 148-6. d, e CT scan of adult Lufengosaurus dentary showing narrow alveolar trough and two stages of tooth replacement (old tooth in red and new tooth in blue) one at the initial stage of development, and the second showing tooth root resorption caused by the growth of new tooth. f Reconstruction of adult Diplodocus. g Computed tomographic scan of adult Diplodocus showing multiple generations of teeth forming in wide alveolar trough without root resorption. Diplodocus YMP 4677 (modified from Figure 2, D’Emic et al.¹).