An international group of scientists from the United Kingdom, the United States, and France has identified what may be the oldest pathogenic fungus known to science, dating back an astonishing 407 million years. The species has been named Potteromyces asteroxylicola to honor Beatrix Potter, the famed British children’s author who also had a keen interest in mycology. The team reported their findings in the journal Nature Communications, a publication widely respected for presenting rigorous, peer-reviewed discoveries in the life sciences.
Potteromyces asteroxylicola was uncovered in fossil material preserved in the Rhynie Chert, a renowned geological site in Scotland known for its exceptional preservation of early terrestrial ecosystems. The team examined a petrified stem segment of the ancient plant Asteroxylon mackiei and, through meticulous study, identified the fossilized structures that indicate a fungal parasitic relationship. A second specimen of the same organism later surfaced in the collections of the National Museums of Scotland, providing additional evidence of the fungus’ ancient existence and its long-standing association with plant hosts in primordial forests.
The discovery raises the intriguing possibility that modern parasitic fungi which target ash trees could be descendants of Potteromyces asteroxylicola. This lineage, if confirmed, would offer valuable clues about how plant-fungal interactions evolved over hundreds of millions of years and how these relationships have shaped forest ecosystems across deep time.
Lead author Dr. Christine Strullu-Derrien explained that, while other fungal parasites have been identified in the Rhynie Chert region before, this find marks the first instance in which a parasite has been shown to directly cause disease in a fossil plant. The study emphasizes the significance of Potteromyces as a key data point for calibrating the timeline of fungal evolution. By connecting ancient infections to modern lineages, researchers can better understand when certain fungal groups diverged and how their parasitic strategies emerged and diversified in relation to plant hosts. This work complements existing paleontological and molecular data, helping to fill gaps in the deep history of fungi and their ecological roles.
In a broader sense, the Rhynie Chert remains one of the most informative windows into the early terrestrial world. Fossils preserved there reveal the roots, stems, and reproductive structures of some of the earliest land plants, along with the organisms that interacted with them. The identification of Potteromyces asteroxylicola adds a new dimension to this picture, illustrating that complex plant-fungal relationships were already part of ecosystems hundreds of millions of years ago. The findings invite further research into how ancient fungi found ways to exploit plant hosts, how those interactions influenced plant growth and survival, and how such dynamics contributed to the development of forest communities in the Silurian period. The study thus not only documents an ancient disease but also helps illuminate the evolutionary context of fungal parasitism and its long-standing impact on plant life across our planet’s deep history, including potential connections to contemporary forest health challenges observed in North American and European woodlands.
As paleobiology and molecular paleontology methods continue to advance, scientists anticipate additional discoveries that will clarify the roots of fungal parasitism and the broader ecological networks of early terrestrial ecosystems. Potteromyces asteroxylicola stands as a pivotal example of how a single fossil find can reshape our understanding of evolutionary timelines and the deep-time roots of organisms that still influence biodiversity and disease dynamics today. The researchers note that ongoing studies of the Rhynie Chert and related fossil assemblages will likely yield more insights into ancient pathogen-host interactions and their enduring legacies for modern biology and ecology. In the meantime, Potteromyces asteroxylicola serves as a remarkable reminder that the history of life on Earth is interwoven with microbial life forms that have shaped the fate of plant communities long before humans walked the planet, and that much remains to be learned about these ancient echoes of disease and survival.