Fig. 1

a SEM image of one representative radula of Lepidochitona cinerea, working zone (Wz), taken from [109]. b, c, e, f SEM image and EDX mapping of the embedded, native radula (working zone) from specimen number 1. c Oxygen (O) distribution. e Iron (Fe) distribution. f Calcium (Ca) distribution. b Red triangles represent the areas of nanoindentation for lateral tooth II (basis, stylus, cusp). d Habitus from one representative specimen, taken from [109]. g Light microscopy image of one native radula, working zone. Central teeth, lateral teeth I, marginal teeth are almost translucent, but slightly yellowish. The cusps of the lateral teeth II are clearly visible due to the high proportions of Fe. h Light microscopy image of one treated radula, working zone. Central teeth, lateral teeth I, and marginal teeth are more translucent. Scale bars: a–c, e–h = 100 μm, d = 5 mm. Ct, central tooth; Lt I, lateral tooth I; Lt II, lateral tooth II; Mt, marginal tooth