Figure 3 in Histological study of the oral teeth and their bony support in the Mexican Jurassic gar †Nhanulepisosteus mexicanus (Ginglymodii, Lepisosteidae)

Figure 3. – †Nhanulepisosteus mexicanus: Histological organization of the fangs (natural transmitted light). A: Axial section of a tooth. The pulp cavity (pc) is totally occupied by axial trabeculae of dentine (de) alternating with pulp spaces. The tooth is fixed on a basement of reconstructed bone (bo). vc = vascular cavities. B-D: Three cross-sections of different levels of a tooth. B: The section is localized at the tooth base; it shows a ridged crown of orthodentine surrounded by a thin layer of enameloid (en). The pulp cavity is occupied by vascularized dentine. On the bottom of the fig, the bone of attachment (bo). C: The section crosses the mid part of the pulp cavity. The tooth is constituted of a crown of orthodentine (de) surrounded by a layer of enamel (en) showing external crests. The pulp cavity is totally occupied by vascularized dentine. D: The section is in the higher part of the pulp cavity. The tooth is constituted of a crown of orthodentine (de) surrounded by the crenulated enamel (en). We can see the pulp cavity which is reduced. E: Cross-section in the mid part of the tooth. Details of the dentine showing the peripheral orthodentine layer (white asterisks), with its ondontoblastic canalicles and the vascular canals fit together. Each canal is surrounded by orthodentine (black arrow-head). The enameloid layer is crenulated (white arrow-heads). A: IGM 4902-5; B: IGM 4902-3; C,E: IGM 4902-2; D: IGM 4902-1. Scale bars: A, B, C = 200 μm; D = 100 μm; E = 50 μm.