Extended Data Fig. 6: PCA comparing negative-ion ToF-SIMS spectra from the corneal facet walls in a fossil crane-fly with various reference materials. | Nature

Extended Data Fig. 6: PCA comparing negative-ion ToF-SIMS spectra from the corneal facet walls in a fossil crane-fly with various reference materials.

From: Fossil insect eyes shed light on trilobite optics and the arthropod pigment screen

Extended Data Fig. 6

a, Score plot from an analysis that includes all major eumelanin peaks in the mass range m/z 48–146 (Supplementary Table 3). b, Associated loadings from PC1 and PC2, with glyphs indicating the ion categories to which each peak is assigned. c, Bar graph comparing the added signal intensities from all peaks in the various ion categories (error bars are ±1 s.d.). In ac, xanthommatin, n = 3 measurements; xanthommatin (matured), n = 3 measurements; Sepia eumelanin, n = 3 measurements; Sepia eumelanin (matured), n = 3 measurements; dihydroxyindole (DHI) eumelanin, n = 3 measurements; DHI eumelanin (matured), n = 3 measurements; dopamine (DA) eumelanin, n = 4 measurements; ink sac of a fossil squid from the Dorset coast, n = 3 measurements; ink sac of a fossil squid from the Posidonia Shale, n = 3 measurements; fossil crane-fly facet walls, n = 7 measurements.

Back to article page