Figure 4. Dentition of Jianchangosaurus yixianensis gen. et sp. nov.

A, Teeth in the upper and lower jaws. Labial surfaces of the right maxillary and dentary teeth and lingual surfaces of the left dentary teeth are exposed. The premaxilla and anterior tip of the dentary are edentulous. B, Anterior left dentary teeth (first and second) in lingual view, showing the convex lingual surface. A replacement tooth is exposed at the root of the second dentary tooth. C, Posterior right maxillary teeth (from fourteenth to twentieth) in labial view. The crown size diminishes posteriorly. D, Middle right maxillary and dentary teeth in labial view. The maxillary teeth exhibit the conventional dental morphology (convex labial surfaces), but the dentary teeth show the reversed dental morphology (concave labial surfaces). E, Middle left dentary teeth (from eleventh to thirteenth) in lingual view, showing the reversed dental morphology (convex lingual surfaces). F, Anterior left dentary teeth in labial view, showing a shelf (red arrows; starting between d6 and d7) and a shift from normal (d4 to d6; convex labial surface) to reversed (d7 and posterior; concave labial surface) teeth. Scale bars on A–F are 1 cm.