For each taxon, an icon shows the specimen regions analysed for Zn enrichment (brighter regions) with synchrotron (a, c, d, h, i, k) or for general elemental composition with SEM/EDS (b, e–g, j, l): green box, eyes; blue box, soft body tissue; red box, feeding structures. In SEM/EDS maps (b, e–g, j, l): red, iron; yellow, sulphur; green, calcium; pink, silicon; purple, phosphorus; blue, aluminium. The EDS cannot capture carbon, so a thin layer of it appears identical to the matrix, and a thick layer appears black. All scale bars 1 mm, except f which is 0.5 mm. a–c, FMNH PF8719, chordate Esconichthys apopyris; (a) eyes enriched in zinc, (b) preserved in pyrite, and (c) body lacking zinc enrichment. d, FMNH PE 39321, unidentified cephalopod, radula and soft tissue lacking zinc enrichment (dark areas are due to relief). e, f, FMNH PF7499, chordate Elonichthys peltigerus; (e) eyes lacking pyrite and (f) teeth preserved in calcium, sulfur, and phosphorus interpreted to reflect the original apatite. g, FMNH PE12371, polychaete Fossundecima konecniorum, jaw apparatus (two light-coloured triangular areas, each with an arrow, on a darker background) preserved in a thin carbon film. h, FMNH PE30643, cnidarian Essexella asherae, tissue lacking zinc enrichment. i, FMNH PE 30054, Etacystis communis, unidentified soft-bodied organism, possibly cnidarian, soft tissue may be slightly enriched in zinc. j, FMNH PE21951, holothurian Achistrum sp., teeth of circular jaw preserved in calcium reflecting the original (calcite) composition. k, FMNH PE15530, crustacean Lobetelson mclaughlinae, eyes lacking zinc enrichment. l, FMNH PE23336, horseshoe crab Euproops danae, telson preserved as a thick carbon film.