PMC

(A) Tooth width and lamellar frequency in the occlusal surface of the upper jaw (r =  − 0.558, t =  − 7.699, p < 0.05). (B) Tooth width and lamellar frequency in the buccal side of the upper jaw (r =  − 0.476, t =  − 6.201, p < 0.05). (C) Tooth width and enamel thickness (ET) of the upper jaw (r = 0.531, t = 7.179, p < 0.05). (D) Width and lamellar frequency in the occlusal surface of the lower jaw (r =  − 0.649, t =  − 7.915, p < 0.05). (E) Width and lamellar frequency in the buccal side of the lower jaw (r =  − 0.453, t =  − 7.523, p < 0.05). (F) Width and ET of the lower jaw (r = 0.457, t = 4.759, p < 0.05).

(A) Coronal section of the jaw and tooth of a juvenile specimen of P. vitticeps ROM R8510 showing minimal ossification of the jaw bone, and pleurodont tooth attachment; (B) close up of a juvenile specimen’s (ROM R8510) dentition, showing unworn morphology; (C) coronal section of a juvenile specimen (ROM R8234) showing pleurodont implantation, and remodeling; (D) closeup of the attachment site in ROM R8234, showing the labial side of the dentition being resorbed by an osteoclast; (E) coronal section of the coronoid process (ROM R8234) showing a tooth developing lingually inside the coronoid and dentary; (F) a close up of the tooth in the jaw bone, showing the resorption of the jawbone around newly developing tooth. Abbreviations: ab, alveolar bone; ac, acellular cementum; cb, cancellous bone; cp, coronoid process de, dentine; dt, developing tooth; lb, lamellar bone; en, enamel; ost, osteocyte lacunae; oc, osteoclast; rb, resorption bay; rl, reversal line. All un-labeled scale bars = 1 mm.

(A) Coronal section of the jaw and tooth of an adult specimen of P. vitticeps (ROM R8507) showing the maintained vasculature and worn enamel on the labial side, in cross polarized light; (B) Coronal section of ‘A’ in normal transmitted light; (C) Coronal section of the jaw and tooth of an adult specimen of P. vitticeps ROM R8507 showing the extensive remodeling of the tooth attachment site as well as the tooth, in cross polarized light; (D) Coronal section of ‘C’ in normal transmitted light. Abbreviations: de, dentine; lb, lamellar bone; en, enamel; vc, vascular canals; rz, remodeling zone. Scale bar = 500 um.

Alveolar tooth socket thickened due to formation of torus. The torus consists entirely of lamellar bone. At the left side the periodontal ligament space with the tooth surface are shown.