Extended Data Fig. 3: Three-dimensional visualization and chemistry of MH 432 melanophores.
From: Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur
a, SRXTM renderings of branched melanophores (sample 18). b, FEG-SEM micrograph of a dermal melanophore and adjacent organic matter recovered from demineralized integument (sample 13a). Note the remnant cell body (arrow) and external moulds of disrupted pigment organelles in the polymerized matrix of one dendrite (arrowheads). c, FEG-SEM micrograph of a dermal melanophore and adjacent organic matter from demineralized integument (sample 13). Note the clustered melanosomes that represent the cell body (arrow), and dendritic extensions packed with pigment organelles (arrowheads). d, Back-scattered electron micrograph and single-element EDX maps of the melanophore in Fig. 3e–g. Coloured images illustrate the relative abundance of each element, with higher intensities indicating greater abundance. Note the enrichment of carbon and, to a lesser extent, sulfur and oxygen in the fossil pigment cell. Intensities from calcium and fluoride derive from the underlying spectrophotometric window (see g). Al, aluminium (lime); C, carbon (red); Ca, calcium (blue); Cu, copper (dark red); F, fluoride (green); O, oxygen (yellow); P, phosphorous (purple); S, sulfur (orange); Si, silicon (turquoise). e, High-resolution NanoSIMS images of the melanophore in Fig. 3h–k showing the distribution of CH−, CN−, P−, S− and CaO−. Note the relatively high levels of CN− and S− in the melanosomes, whereas the surrounding matrix also contains measurable amounts of CH− and P−. f, The alkaline hydrogen peroxide oxidation products PTCA, PDCA and PTeCA (Fig. 3r) from samples 7a (two batches), 10a (two batches), 10b, 13a, 13d and 14a (two batches). g, Infrared spectrum from the melanophore in Fig. 3e–g (arrowhead in the inset light microscopy image) showing peaks attributed to hydrocarbons and phosphate.
