FIGURE 1. Details of the fossil locality. A , Map of eastern Australia showing the extent of the Surat Basin within the Great Artesian Basin complex, and the location of Lightning Ridge. B , Map showing the location of the Coocoran Opalfield (after Smith and Smith, 1999) and extent of the Griman Creek Formation (after Frauenfelder et al., 2021). C , Cretaceous stratigraphy of the southern Surat Basin (after Bell et al., 2019).
FIGURE 2. Illustrations of opalized termite coprolites from the Griman Creek Formation, Lightning Ridge (all images of specimen AM F 128064). A , Overview of specimen. B , Details of irregularly arranged pellets. C , Details of hexagonally prismatic faecal pellets. D , Details of faecal pellets and remnants of intervening clays and opaline silica. E , Greyscale tomographic reconstruction of fossil frass showing a mix of pellets with uniform and hollow interiors; hexagonal shape is evident in the cross-section in the coprolite on the right. F , Greyscale tomographic (μCT) reconstruction of fossil frass showing pellets in longitudinal (oblong) and transverse (hexagonal) section. G , Greyscale tomographic (µCT) reconstruction of fossil frass showing pellets held together by porous clays or opaline silica. H , Scanning electron micrograph of hexagonally prismatic coprolites. I , Scanning electron micrograph of hexagonally prismatic coprolites with blunt termini. J , Scanning electron micrograph of coprolites showing details of truncate termini. Scale bars equal 10 mm for A; 1 mm for B-G; 500 µm for H-J.
FIGURE 3. Energy-Dispersive X-ray Spectroscopy (EDS) plot for coprolites showing overwhelming dominance of silicon and oxygen X-ray counts denoting opaline composition of the fossils.
