Fig. 5

Spectral analysis of the dorsal protrusion region. a NEXAFS image related to the nitrogen K-edge region at 395–420 eV. This spectral range corresponds to nitrogen bonds at the surface. b Image related to the calcium L-edge (345–350 eV). The presence of both nitrogen and calcium may be interpreted as biomineralized tissue near the scarab dorsal protrusion of the head. c Oxygen NEXAFS image in the 530–550 eV region. d Spectra extracted from the dorsal protrusion of the head. Areas marked in black or white indicate the position of albumin (top) and chitin (bottom) reference materials. All images and spectra are pre-edge normalized. e Photograph highlighting the surface chemistries found on the head of E. gralli