Leo 1530 vp scanning electron microscope

Sampling. The specimen NJU-57003 is represented by two fragmented slabs, both containing original bone, fossilized soft tissues, and natural moulds of bones. Each slab was glued together along the fissures by fossil dealers with the fossil on the surfaces untouched. The specimen CAGS-Z070 is represented by a single unbroken slab. Small flakes (1-3 mm wide) of samples with preserved integument and/or enclosing sediments were carefully removed from the inferred integumentary filaments from different parts of NJU-57003 (Supplementary Figs. 1a and4a-c) using a dissecting scalpel. This method was used to avoid sampling from degraded products of other tissues, such as dermis, epidermis, or even internal organs. Most samples were not treated further; the remainder were sputter-coated with Au to enhance SEM resolution (Fig. 2g-h and Supplementary Figs. 4a-f and6). All experiments described below were repeated in order to validate the results. SEM. Samples were examined using a JEOL 8530F Hyperprobe at the School of Earth Sciences, University of Bristol, and a LEO 1530VP scanning electron microscope at the Technical Services Centre, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences. Both instruments were equipped with a secondary electron (SE) detector, a back-scattered electron (BSE) detector and an energy dispersive X-ray spectrometer (EDS).