Extended Data Fig. 7: Immunoreactivity of fossil ichthyosaur and extant leatherback sea turtle skin.
From: Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur
a–t, Immunohistochemical staining and immunogold labelling of demineralized MH 432 skin (samples 8 and 12a) (a–h) versus experimentally treated D. coriacea skin (i–t), exposed to antibodies raised against Bos taurus elastin (a, b), G. domesticus actin (c, d), A. mississippiensis collagen (e, f, k, l), G. domesticus feathers (indicative of β-keratin) (g, h), G. domesticus tropomyosin (i, j), A. mississippiensis haemoglobin (m, n), S. camelus haemoglobin (o, p) and G. domesticus α-keratin (q–t). Images in a, c, e, g, i, k, m, o, q show where the antibodies bind to tissue (green) superimposed on transmitted light images. Fluorescein isothiocyanate fluorescence in b, d, f, h, j, l, n, p, r indicates binding for all antibodies except β-keratin. In D. coriacea, the migration from the epidermis to underlying tissues of compounds derived from α-keratin probably reflects the combined effects of decay, compaction and maturation. De/hy, dermis and hypodermis (corresponding to blubber in adult D. coriacea); epi, epidermis. s, t, Low-resolution (s) and high-resolution (t) localization of anti-α-keratin antibody tagged with gold to fibrous matter in D. coriacea skin. Note the filamentous structures (arrowhead).
