Extended Data Fig. 7: Experimentally treated N. suturalis corneas.
From: Fossil insect eyes shed light on trilobite optics and the arthropod pigment screen
a–i, Light microscopy images showing the visual appearance of the corneas (n = 1,300 sampled crane-flies) after the following sequential treatments: aqueous extraction with grinding (a), proteinase K and DTT (step 2; Supplementary Information) (b), protease and DTT (step 4) (c), chitinase (step 5) (d), proteinase K and DTT (step 6) (e), chitinase (step 7) (f), chitinase (step 9) (g), protease and DTT (step 11) (h) and heptane and HCl(aq) (i). Inset shows a FEG-SEM micrograph of the isolated corneal facet walls. All experiments were repeated twice independently with similar results. Scale bars, 30 μm (inset of i), 500 μm (a).
