Researchers from the University of Cambridge and the Natural History Museum in London have identified a new species of ancient symbiotic fungus within a 407-million-year-old plant fossil found in Scotland. The study provides detailed three-dimensional insight into early plant-fungus partnerships, known as mycorrhiza.
Mycorrhizal fungi live inside plant roots and help absorb water and nutrients such as phosphorus. This type of relationship supports most plant life today and played a key role when plants first adapted to life on land.
The research team used advanced microscopy techniques to distinguish the fungus from surrounding plant cells. By analyzing unique light signatures preserved in fossils, scientists can now detect traces of ancient organisms long after their DNA is gone.
Their findings are published in New Phytologist. The paper describes Rugososporomyces lavoisierae, a new species of arbuscular mycorrhizal fungus that formed a symbiotic relationship with Aglaophyton majus, an early land plant. This is only the second fungal species known to have been hosted by this particular plant.
The fossil, which comes from the Windyfield Chert in Scotland, offers the most detailed evidence so far that early land plants engaged in complex relationships with more than one fungal species over 400 million years ago.
Professor Sebastian Schornack, Group Leader at the Sainsbury Laboratory Cambridge University and co-leader of the study, said: “This is just the start. By applying these methods to the fossilised remains of different organisms, we now have a powerful new tool to tell apart structures that may look similar but differ in their fine ultrastructure, for example ancient arthropods, plants and fungi.”
He added: “This technique adds a new dimension to how we identify, describe and discriminate fossilised ancient life, using the unique light signals these materials emit as a kind of fingerprint. Although the original biological material is fossilised and no DNA remains, these optical signatures preserve vital clues to their identity.”
Using similar techniques with other fossils from Windyfield and nearby Rhynie cherts may help researchers understand how early partnerships between plants and fungi evolved.
The analysis brought together experts from several institutions: Natural History Museum staff who discovered the fungus; teams at Muséum d’Histoire Naturelle in Paris who contributed brightfield microscopy; specialists at Sainsbury Laboratory Microscopy Core Facility who performed confocal fluorescence lifetime imaging microscopy (FLIM) and Raman imaging; and members of Cambridge Graphene Centre responsible for Raman spectroscopy.
Dr Raymond Wightman, Manager of Sainsbury Laboratory Microscopy Core Facility who led FLIM imaging work said: “By combining confocal fluorescence lifetime imaging with Raman spectroscopy, we can chemically identify ancient microscopic life forms with remarkable precision. Our new technique is opening an exciting new window on life’s earliest chapters.”
The fossil analyzed was held at National Museum of Scotland in Edinburgh. Dr Christine Strullu-Derrien from Natural History Museum prepared it for study and co-led research efforts.
“Mycorrhizas are very rare in the fossil record and have never been found in the Windyfield Chert before. The presence of the arbuscule shows that the fungus wasn’t parasitising on the plant or feeding on it after death – instead, there was a symbiotic association. The fungus would have provided minerals like phosphorus in return for sugars from the plant in a way that benefits them both,” said Dr Christine Strullu-Derrien.
This newly discovered partnership closely resembles modern arbuscular mycorrhizal associations important for present-day soil health.
Reference: Christine Strullu-Derrien et al., ‘An arbuscular mycorrhiza from the 407-million-year-old Windyfield chert identified through advanced fluorescence and Raman imaging.’ New Phytologist, Nov 2025. DOI: https://doi.org/10.1111/nph.70655.