Figure 2
AFM vertical deflection images depicting the shape of longitudinally and transversely cut fibres as well as the internal structure of fibres of the modern brachiopod Magellania venosa. The corresponding lateral deflection images are shown in Fig. A2. (a) Nanometric internal structure of single-crystalline fibres. These nanometric units (nanometric biocalcite crystallites, NBC) are often strung in rows (white arrows in (a) following the convex shape of the proximal, convex basal part of a fibre and depict growth lines. White stars point to the organic membrane that lines the proximal, convex surface of fibres. (b) One star indicates the apical, concave part of a fibre; two stars point to the proximal, convex portion of a fibre.
