a, Polygonal surface structure of the red-brown organ trace (arrowheads). Note the irregular patches of phosphatized adipocere (A) overlying the mineralized internal structure, and a vertebral centrum (vert) that has penetrated the decomposing tissue before fossilization. b, Light microscopy section through demineralized liver matrix (sample 1), which reveals its layered architecture that is probably produced by diagenetic compaction. c, FEG-SEM micrograph of pliable organic matter released via treatment with EDTA (sample 1). d, Enlargement showing a degraded and somewhat fibrous (arrowheads) biomass. e–h, Overlay (e, g) and fluorescent (f, h) images of demineralized liver material (sample 7) exposed to antibodies raised against A. mississippiensis (e, f) and S. camelus haemoglobin (g, h). i, TEM micrograph of probable cellular membranes (arrowheads). j, TEM micrograph showing a dense melanosome cluster (sample 1). k, Positive ion ToF-SIMS spectrum with peaks characteristic of aliphatics (triangles) and polyaromatics (circles; sample 1).