Extended Data Figure 9: Analysis of putative Genyornis oological eggshell material.

A, Scanning electron micrographs of sample 1 from square 4C, quadrat B, spit 18. Aa, view of a fresh broken edge showing a smooth eroded-out surface (upper), a section through a pore canal; Ab, detail of the pore canal opening showing the material filling pore; Ac, detail of the inner layer 1 and smooth inner surface of the shell showing that it is slightly eroded, so that the tips of the mammillary cones of layer 1 are lost; Ad, outer surface of the shell showing an elongated pair of pore canal openings occluded by material; Ae, outer surface of the shell showing the rounded eroded edge of the fragment; Af, outer surface of the shell and another opening to a pore canal showing its elongated nature and occlusion by material. B, Scanning electron micrograph views of an eggshell of Anseranas semipalmata (sample from the South Australia Museum B.14591) showing the cross-section on the left and a detail of the accessory layer on the right. Note that the accessory layer comprises an amorphous mass of similar sized spheres, a structure that typifies the accessory layer of many galloanseres, including that of putative Genyornis material. C, Element-profile plot across the pore aperture shown in Ab. The sides of the pore are at approximately 40 and 90 μm on the x axis and on either side the profile reflects the dominant CaCO₃ nature of eggshell. Within the pore, elevated levels of iron (Fe), silica (Si) and aluminium (Al) are present.