FIGURE 4. Close-up RTIViewer snapshots of the region dorsal to the dorsal vertebral column on the main slab, taken under different lighting conditions but all processed using the specular enhancement mode (except for Figure 4A). Scale bar for all illustrations equals 10 mm. Comment on the settings in the RTIViewer software as visualised in the figures. A green sphere symbolises the direction of the incident light (upper right corner), a text box in the upper image margin contains the respective x- and ycoordinates of the incident light direction (the first value contains the x-coordinate, while the second one contains the ycoordinate), the zoom factor is given in brackets. A second text box contains the individual values of the specular enhancement mode (lower left corner). The first value stands for the parameter "specularity", the second one indicates the parameter "highlight size". The line drawings were sometimes made based on several RTI images with different settings to illustrate an individual impression more clearly. As far as the figures themselves are concerned, the interpretative drawings have tried to come as close as possible to the appearance and arrangement of the structures observed in the RTIViewer. However, some drawings, such as Figure 4B, represent rather idealised illustrations of the general pattern and arrangement of individual pycnofibre impressions in a given area. For this reason, the interpretative drawings may differ in detail from the respective RTI images to which they refer. In all figures, the orientation of the pycnofibres is marked by red arrows; the whitish semicircular indent, the starting point of most of the pycnofibres in the caudal region of the dorsal vertebrae, is symbolised by a red arc throughout Figure 4 and 5, the single occurrence of Type 2 pycnofibres is circled in red in the aforementioned figures. 4A. Overview of the pycnofibre impressions in the area dorsal to the dorsal vertebral column associated with the whitish amorphous rock surface under normal light. 4B. Interpretative drawing of Figure 4A (dorsal ribs in the lower right corner of the image) under normal light, idealised to give an overview of the spatial orientation of the pycnofibre impressions and therefore not reflecting the exact path of individual impressions. Thicker lines indicate better observable impressions. 4C. The same area as in 4A, seen under the specular enhancement mode. 4D. Pycnofibres of the caudalmost part of the area dorsal to the dorsal vertebral column (lower right corner). Note the pycnofibres showing a distinctive cross-over (red circle in 4D and 4E), representing Type 2. 4E. The same area as in 4D under other lighting conditions to highlight the overlapping impressions.

Published as part of Henkemeier, Nils, Jäger, Kai R.K. & Sander, P. Martin, 2023, Redescription of soft tissue preservation in the holotype of Scaphognathus crassirostris (Goldfuss, 1831) using reflectance transformation imaging, pp. 1-40 in Palaeontologia Electronica (a16) 26 (2) on page 11, DOI: 10.26879/1070, http://zenodo.org/record/11063386