Extended Data Fig. 6: Chemistry of SSN8DOR11 chondroderms.

a, Ground section through a proximal chondroderm (n = 3 samples). b, EDX mapping of the two main chemical elements, calcium (Ca; turquoise) and phosphorous (P; green), present in the dermal mineralization (n = 3 analyses). c, Infrared spectrum from the sectioned chondroderm (star in the inset heat map; each pixel represents 512 coadded scans) showing a distinct peak at 1,044 cm⁻¹ that matches the asymmetric \({v}_{3}({\rm{P}}-{{\rm{O}}}_{4}^{3-})\) mode of calcium phosphate. d, Infrared spectrum from organics (star in the inset heat map; each pixel represents 1,024 coadded scans) recovered from a demineralized chondroderm. The marked region, ~2,800–3,000 cm⁻¹, corresponds to C–H stretching modes. e–h, ToF-SIMS data acquired from organic and inorganic matter liberated from a demineralized chondroderm. e, Images of positive ions showing sub-spherical (‘cellular’) bodies containing either calcium phosphate (Ca_xPO_y) or a mixture of zinc (Zn), silver (Ag), sulfur (S), and chlorine (Cl) embedded in an organic matrix comprising polyaromatic hydrocarbons (PAHs). f, Positive-ion spectra from the regions of interest (ROIs) indicated in the three-colour overlay image in e, representing the organic matrix (blue), Zn/Ag/S/Cl (green) and calcium phosphate (red), respectively. g, Images in negative mode (same area as in e) of ions associated with calcium phosphate (PO_x) and the Zn/Ag/S/Cl mixture, together with a three-colour overlay image of the two main types of chondrocyte-like bodies depicted in red and green, respectively, and ‘typical’ PAH ions in blue. h, Negative-ion spectra from the ROIs indicated in the overlay image in g representing the organic matrix (blue), Zn/Ag/S/Cl-containing particles (green) and calcium phosphate (red). Ions representing the three materials are listed in Table S1. Data in e–h are representative of eleven independent measurements from eight areas on two samples. Scale bars, 500 µm (a), 50 µm (d).