Extended Data Fig. 4: Cranial anatomy of T. alcoberi on the basis of 2D cross-sectional slices from micro-computed tomography scan data.

a–c, Transverse cross sections of the skull showing the paired nasals (a), frontals (b) and parietals (c). d, Longitudinal cross-section of the paired frontals. e, Transverse cross section of the left lower and upper jaws in anterior view, showing labial and lingual walls of the tooth grooves of the maxilla and dentary. f, Transverse cross section of the posterior region of the skull through the braincase and the left lower jaw in anterior view. g, Transverse cross section of the left maxilla, showing the replacement tooth going into position. h, Longitudinal cross-section of the left dentary in occlusal view. i, j, Longitudinal cross section of the anterior (i) and posterior (j) sectors of the right maxilla in occlusal view. In h–i, the absence of the interdental ridges and less dense attachment tissue (alveolar bone and/or cementum) in the interdental space of the anterior dentition is shown, whereas j shows the direct contact between the posterior teeth and the absence of interdental space. Planes of the sections in the corresponding details. ac, adductor crest; alv.t., alveolar tissue; de, dentary; mx, maxilla; na, nasals; f-f, inter-frontal suture; fr, frontals; la, labial wall; li, lingual wall; ot, otolith; pa, parietals; pof, post-frontal; prf, pre-frontal; rp, resorption pit; rt, replacement tooth; to, tooth. Scale bars, 1.5 mm (a), 1 mm (b–e, h–j), 2.5 mm (f), 2 mm (g).