Extended Data Fig. 9. Taphonomy of P. antiquus preserved in the Nanfen mudstone.

a–b, A partially exposed specimen. b is a backscattered electron scanning electron microscopy (BSEM) photograph of the same specimen in a. VPIGM-4794. c, Energy dispersive X-ray spectroscopy (EDS) point analysis at the blue spot in b, showing the presence of carbon in the fossil specimen. d, EDS elemental maps of labeled box in b, showing the enrichment in C and deficiency in O, Al, and Si in fossil relative to matrix. e–g, Nanfen mudstone fractured obliquely relative to bedding plane, showing darker-colored fossil layers and lighter-colored background layers. f and g are magnifications of labeled boxes in e. h–i, Polished slab cut perpendicular to bedding surface, showing darker-colored fossil layers and lighter-colored background layers. i is a close-up view of labeled box in h with blue arrowheads denoting fragmented fossils in a fossil layer. All photos taken by authors.