Figure 4 in Paleohistological studies of bone and teeth in Gyrodus circularis (Gyrodidae: Pycnodontiformes: Actinopterygii). Phylogenetic implications for the Gyrodidae

Figure 4. – Gyrodus circularis. Ground transversal sections of the teeth roots (transmitted natural light). A: (MNHN-F-Histos 2748) Detail of the orthodentine (od) showing the apical part of the odontoblastic canalicles that are clearly ramified to their extrem- ity (arrows); bo: bone. Inset: detail of a terminal ramification. B: The section (MNHN-F-Histos 2748) shows the contact between the orthodentine (od) with the alveolar bone (bo). The pulp surface of the dentine shows thin mineralized spherules (arrowheads) that project in the pulp cavity; pc = pulp cavity; vc: vascular cavity. C: (MNHN-F-Histos 2743) Detail of the spheritic orthodentine showing the Liesegang lines that mark the successive steps of mineralization in proportion of the thickening of the tooth. The upper Liesegang line is edged by mineralized spherules. The black arrowheads point to the more recent mineralized spherules that project in the pulp cavity (pc). Inset: Detail of several mineralized spherules (white arrowheads) inside the dentinous tissue (arrows). Scale bars: A = 25 μm; Inset A = 10 μm; B = 50 μm; C = 50 μm; inset C = 25 μm.