Dwarf emu eggs retained large size: Supplementary material

For intact eggs, all measurements were taken using dial calipers and rounded to the nearest 0.1 mm, with a micrometer rounded to the nearest 0.1 mm for eggshell thickness. Total length of complete eggs was taken along the long axis, and greatest width along the short axis at the widest medial point. Circulation of egg volume from museum eggs, including extinct taxa, used methodology described in [17]. Eggshell thickness was measured in the blowhole region of intact eggs, as described in [18], and recent museum and subfossil eggshell fragments were measured away from eroded or broken edges.