Figure 2 in Moa's Ark: Miocene Fossils Reveal the Great Antiquity of Moa (Aves: Dinornithiformes) in Zealandia

Figure 2. SEM image of a broken cross-section of "thick" Miocene fossil eggshell from the St Bathans deposits (NMNZ S.40938.9) showing the structure. The upper surface is the external layer of the shell. EZ = external zone, SZ = squamatic "spongy" zone, MZ = mammillary zone. Features consistent with moa eggshell include (a) the mammillae consisting of tabular wedges; (b) the mammillae being higher than wide; (c) the vesiculation in the MZ being weak or absent; (d) the absence of a resistant zone between the SZ and EZ; (e) the EZ being blocky (see Appendix 2).