Microscopic algae may have helped preserve 22.5-million-year-old spider fossils

Sticky sulphurous secretions thought to be behind rare fossils of non-mineralised structures.

photography of a spider fossil in rock overlaid with fluorescent microscopy image
A fossilised spider from the Aix-en-Provence formation overlaid with a fluorescent microscopy image of the same fossil, displaying its fluorescence under UV light. Credit: Alison Olcott.