Fig. 2
Synchrotron x-ray microtomographic images of Hesperornis dentary. Anterior part of the dentary of Hesperornis regalis YPM.1206.A, showing the implantation location of the preserved teeth. a Lingual view showing by transparency four teeth (TH1 to TH4) and some preserved cementum of one tooth (THc) present in the groove. b Horizontal volume section of the dentary showing the groove and its constriction, in occlusal view. c Horizontal section at mesial end. d parasagittal section along groove at mesial end. A small hole, that we interpret as a minute alveolus, is visible at the dentary mesial extremity (c, d). It communicates with the groove through a ventrally situated “tunnel”. e Transverse volume section through the middle of the insertion location of a (missing) tooth. f Transverse volume section through a constriction of the groove adjacent to (and delimiting) the preceding. Labial to the groove is the medullary cavity running parallel along the jaw. g Virtual transverse section of the same constriction as in f: it appears that it is shaped as a bulge of jaw bone tissue. Scale bars a, b 2.5 mm, c, d, e, f 1 mm, g 0.15 mm