Fig. 3: Cartilaginous integumentary deposits.
From: Adaptations for stealth in the wing-like flippers of a large ichthyosaur
a, Chondroderms near the base of the trailing edge. b, Chondroderms supporting the mid-distal portion of the trailing edge. The region in the box is enlarged in c. c, Chondroderms reinforcing the sinusoidal trailing edge. d, Chondroderms at the tip of the flipper. The framed region is shown in e. e, Magnification of a distal chondroderm. f, Micro-computed tomography (μCT) visualization of the same element. 3D rendering of the exposed surface (left) and semi-transparent 3D reconstruction of the chondroderm in planform (centre) and anterior (right) views (see also Supplementary Video 1). Chondrocyte lacunae occur as turquoise and red dots (n = 2 specimens). g, FEG-SEM micrograph of the granular chondroderm exterior (n = 5 specimens). h, Synchrotron radiation X-ray tomographic microscopy (SRXTM) rendering of chondroderm cartilage (see also Supplementary Video 2). Artificial colouring reflects density variances (yellow, higher density; magenta, lower density) related to recurring differences in the degree of phosphatization between the territorial and interterritorial matrix, indicating both biological and diagenetic mineralization49 (n = 4 samples). Inset, isogenous groups of cell-like structures embedded in phosphatic matrix. cd, cell doublet; cs, cellular structure; itm, interterritorial matrix; tm, territorial matrix. i, Mouldic preservation of a cell doublet (FEG-SEM micrograph) (n = 5 samples). j, Ground section of chondroderm calcified cartilage (FEG-SEM micrograph) (n = 3 samples). Note globular organization (brackets) and Liesegang banding patterns (arrowheads). k, Chondrocyte lacunae containing pigmented matter consistent in appearance with cartilage cells. l, FEG-SEM micrograph of a carbonaceous chondrocyte after demineralization (n = 2 samples). m, Cell doublet with mitotic junction (arrow) and associated extracellular matrix (arrowheads) liberated from demineralized chondroderm cartilage (FEG-SEM micrograph) (n = 2 samples). Scale bars, 3 cm (b), 5 mm (a,c,d), 1 mm (e), 50 µm (g,h,j,k), 10 µm (i,m), 5 µm (l).
