Extended Data Fig. 4: Soft tissues of Temnodontosaurus specimen SSN8DOR11.
From: Adaptations for stealth in the wing-like flippers of a large ichthyosaur
a, Counterslab (left) and slab (right) sections showing soft tissues adhering to a phalanx (arrowhead), in addition to forming a bedding-parallel coating underneath the skeletal elements (arrows). b, Flexible organic residue after treatment with EDTA (n = 3 samples). c, FEG-SEM micrograph depicting melanosomes (arrowheads) and fibrous matter (arrows) liberated from demineralized soft tissue (n = 3 samples). d, Interpretative line drawing of the tissue layers preserved in SSN8DOR11 (not to scale): (1) epidermis with melanophores; (2) amassed melanosomes (representing the epidermal–dermal interface and superficial dermis); (3) fibre bundles; and (4) a phosphatic crust. e, Internal view of the stratified soft parts (LM micrograph; numbers as in d). f, Back-scattered electron micrograph and EDX maps of a melanophore (represented by aggregated melanosomes) in phosphatized matrix. Coloured images illustrate the relative abundance of each element, with higher intensities indicating greater abundance. Note localized enrichment of carbon (C; red) in the melanophore, whereas intensities from calcium (Ca; turquoise) and phosphorous (P; green) derive from the fossilized epidermis. Data are representative of five independent analyses. g, ‘Dashed line’ pattern (arrowheads) in the skin of SSN8DOR11. h, Comparable pattern (arrowheads) in Phocoena phocoena integument created by tangentially sectioned epidermal rete pegs. i, Leading edge (le) of SSN8DOR11. Arrows show the main fibre angles. sed, sediment. j, Leading edge of a sectioned P. phocoena flipper. epi, transversely sectioned epidermis; fib, fibrous tissues. k, Fibre bundles arising from the notched anterior margin of a phalanx of digit II. The primary fibre bundle direction is indicated by an arrow. Scale bars, 2 cm (a), 2 mm (e, g–k), 500 µm (b), 10 µm (f), 2 µm (c).
