Figure 2. 3D model of the radula to introduce the nomenclature of tooth regions and the sites that were tested. A. Radula from above. B. Radula from the side. C. The individual teeth from above. D. From below. E. Teeth from medial view, the red line indicates a cross section, from where point-measurements were taken via EDX. F. Schematic outline of a characteristic polished section area of a tooth. When this area was on display, the inner structure and the surfaces could be tested with point-measurements via EDX. The surface was separated into different regions (surface of e.g., the bulge, the stylus, the sides). Abbreviations: BA, basis; BU, bulge; CU, cusp; DE, denticle; IL, inner lateral; IS, inner structure; OL A, outer lateral A; OL B, outer lateral B; OL C, outer lateral C; OL D, outer lateral D; OL E, outer lateral E; SB, basis of stylus; SI, side; ST, terminal stylus; SU, surface.