Discovery of Ancient Parasitic Fungi in 99-Million-Year-Old Amber

In a groundbreaking study published in the June 2025 issue of the *Proceedings of the Royal Society B: Biological Sciences*, researchers have unveiled two new species of parasitic fungi, *Paleoophiocordyceps gerontoformicae* and *Paleoophiocordyceps ironomyiae*, found in 99-million-year-old Kachin amber from Myanmar. This discovery sheds light on the complex evolutionary relationship between fungi and insects during the mid-Cretaceous period, a time when these organisms coexisted in diverse terrestrial ecosystems.

The fossilized fungi are from the same family as the well-known zombie-ant fungus, *Ophiocordyceps unilateralis*, which has captivated popular culture as the inspiration for the video game and TV series, *The Last of Us*. Professor Edmund Jarzembowski, a paleontologist at the Nanjing Institute of Geology and Palaeontology and the Natural History Museum in London, noted, "Insects and fungi have coexisted for over 400 million years, evolving intricate ecological relationships such as mutualism, predation, and parasitism."

The fungi were discovered in amber collected from a mine near Noije Bum Village, northern Myanmar. The research team, led by Yuhui Zhuang and including notable experts from various institutions, emphasized the rarity of such findings, as fossil evidence of parasitic fungi is scarce due to their soft tissues' poor preservation in ancient remains. Dr. Zhuang, the lead author of the study, remarked, "This discovery offers a rare glimpse into parasites from a very long time ago."

*Paleoophiocordyceps gerontoformicae* was identified on a young ant, while *Paleoophiocordyceps ironomyiae* was found on a fly. The infection process begins when a spore contacts a suitable host, germinates, and penetrates the insect's cuticle. The fungus then proliferates within the host, ultimately leading to its death and the emergence of spore-producing structures. Professor Jarzembowski added that these fungi likely played a critical role in controlling insect populations during the Cretaceous, similar to the function of their modern relatives.

This research not only uncovers the early evolution of insect-fungal associations but also highlights the ecological significance of entomopathogenic fungi in regulating insect populations. The authors noted that while these parasitic fungi are prevalent in contemporary ecosystems, their historical counterparts remain largely enigmatic due to the challenges of fossilization.

As the scientific community continues to explore the evolutionary dynamics of fungi and insects, this discovery may pave the way for further research into ancient ecosystems and the ecological roles of these fascinating organisms. The implications of this study extend beyond paleontology, offering insights into the evolutionary adaptations of life on Earth during the age of dinosaurs, which can inform contemporary ecological understandings and conservation efforts.