Scientists Describe "D. rex," a Giant Fungus From Yunnan's Forests
A newly named species forms the largest fruiting structures documented in its group, and it belongs to an entirely new fungal family.
A team of researchers in China, Thailand and Mexico has described a striking new fungus from the forests of Yunnan Province: *Dianjunus rex*, nicknamed "D. rex." Their paper, published on September 29 in *Frontiers in Fungal Biology*, says it forms the largest fruiting structures documented in the Ascomycota, the huge fungal group that includes yeasts, morels and many molds.
What they found
The fungus grows upright from the roots of dying trees, and was collected at several sites in Yunnan, including Luquan County near Kunming and Mengla County in Xishuangbanna. The holotype specimen was associated with the roots of a Chinese cork oak (*Quercus variabilis*).
- Size: fruiting structures (called stromata) stand roughly 20 to 50 centimetres tall
- Classification: a new genus and species, and the first member of a new family, Dianjunaceae
- Closest relatives: the family sits next to Graphostromataceae within the order Xylariales
- Methods: the team combined physical description with DNA and genome analysis
An ancient lineage
Using a molecular-clock analysis of genome-scale data, the authors estimate the new family arose in the early Paleocene, around 65 million years ago, with a wide uncertainty range of 50 to 80 million years. That would place its origins soon after the mass extinction that ended the age of the dinosaurs. It is a statistical estimate rather than a fossil date.
Why it matters
Finding a new fungal *family*, not just a new species, is rare, and it suggests that large, conspicuous organisms can still go unnoticed in well-visited forests. Corresponding author Indunil Senanayake of the Kunming Institute of Botany told Good News Network that the find shows how much fungal diversity is still undiscovered in East Asian forests.
What's next
The paper describes the species and its relationships; it does not make claims about uses for people. Further surveys and sequencing should show how widespread the fungus is and what role it plays underground.
*Also reported by Good News Network.*
