Extended Data Fig. 1: Incremental features of the teeth of Pantolambda bathmodon.

(a) Overview of coronal section of deciduous ultimate upper premolar of NMMNH P-27844 under plane-polarized light (left) and cross-polarized light with a lambda filter (right), showing locations of inset images. (b,c) Photomontages of the protocone exposed for the enamel (b) and the dentine (c), showing excellent preservation of incremental features, neonatal line (dashed line), and locations of close-up images. (d) Contrast-enhanced close-up of lines of von Ebner preserved in the dentine (arrows), extending parallel to the dentinoenamel junction and perpendicular to dentine tubules, and neonatal line (large arrow). (e) Contrast-enhanced close-up of enamel cross-striations and daily laminations (arrows) in the enamel, extending sub-parallel to the dentinoenamel junction and perpendicular to the enamel prisms. Images in b–e are under cross-polarized light. Abbreviations: NNL, neonatal line. Scale bars: 1 mm (a), 200 µm (b, c), 100 µm (d, e).