Scientists have discovered a giant new fungus in the forests of Yunnan, China, whose upright reproductive structures reach 50 centimetres in height and weigh up to 2.2 kilograms, making it the largest known fruiting body among ascomycete fungi. Evolutionary analysis suggests the lineage of the fungus, named Dianjunus rex and nicknamed 'D-rex', dates back roughly 65 million years to just after the extinction of the non-avian dinosaurs.
Researchers from the Kunming Institute of Botany of the Chinese Academy of Sciences identified the new species while surveying temperate coniferous forests near Damaidi and Yipinglang, and tropical rainforest near Nanbang in Yunnan province. The team observed unusually large, whitish reproductive structures, known as stromata, growing from the woody roots of Chinese cork oak trees.
Genetic analysis and examination of the fungus's physical features revealed that it represents not only a new species but also a new genus and an entirely new family, Dianjunaceae, within the order Xylariales. Its closest known relative is Graphostroma platystoma, a fungus that grows on dead hardwood across the Northern Hemisphere.
"This remarkable species represents a new fungal family, Dianjunaceae, and provides a rare window into the evolution of extreme fungal body forms," said Dr Indunil C Senanayake, an associate professor at the Germplasm Bank of Wild Species of the Kunming Institute of Botany and corresponding author of the study published in Frontiers in Fungal Biology.
The fungus produces spores within tiny sac-like structures, unlike familiar mushrooms. Researchers believe it uses enzymes to decompose dead wood and obtain nutrients.
Using a molecular clock technique, the scientists compared the fungus's DNA with genomic information from hundreds of other fungi. Their results indicate the Dianjunaceae lineage originated approximately 65 million years ago, about one million years after the Cretaceous-Paleogene mass extinction that eliminated non-avian dinosaurs.
"After the mass extinction, forests experienced dramatic changes, including the sudden availability of large amounts of dead plant material," said Senanayake. "For wood-associated decomposing fungi, such environmental disruption may have created new ecological opportunities."
Before this discovery, the tallest known ascomycete fruiting bodies measured about 20 to 30 centimetres. The researchers suggest that D-rex's exceptional height may aid spore dispersal by wind above dense vegetation, though the energy cost of growing such a large structure would be significant.
"A fruiting body which towers above surrounding vegetation and debris could have better dispersal of spores by wind in dense forests," Senanayake hypothesised. "However, such a large structure requires substantial energy investment, suggesting that this strategy likely evolved only where the ecological benefits outweighed the costs."
The discovery highlights the potential for further finds in China's subtropical forests, where diverse habitats and stable climatic conditions may support unusual fungal species. The scientists expect continued exploration will reveal additional unexpected forms and evolutionary histories.
Analysis
Why This Matters
- The discovery rewrites the upper size limit for ascomycete fruiting bodies, previously thought to max out at around 20-30 cm.
- The timing of the lineage's origin, just after the dinosaur extinction, offers a rare case study of how mass extinctions can create ecological opportunities for decomposer organisms.
- The find underscores how poorly understood fungal biodiversity remains in East Asian forests, with significant implications for conservation and bioprospecting.
Background
Fungi of the phylum Ascomycota include more than 64,000 recognised species. Unlike basidiomycetes (mushroom-forming fungi), ascomycetes produce spores in tiny sac-like structures on or inside their fruiting bodies. The order Xylariales is known for producing specialised enzymes and chemical compounds. China's Yunnan province is a biodiversity hotspot with diverse forest types, but its fungal life has received less scientific attention than its plants and animals, partly due to difficult terrain and the seasonal, hidden nature of many fungi.
Key Perspectives
What to Watch
- Whether further surveys in Yunnan's forests turn up additional members of the Dianjunaceae family or other unusually large ascomycetes.
- Studies of the enzymes produced by Dianjunus rex, which may have biotechnological applications for breaking down plant material.
- Molecular clock analyses of other wood-decaying fungi in the region, which could reveal whether the post-extinction period triggered a broader radiation of decomposer lineages.
Checked
12 claims in this story checked against 1 source: 11 supported.
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- SupportedThe giant fungus nicknamed D-rex was discovered in forests in Yunnan, China.Latest Science News -- ScienceDaily: “Scientists exploring the forests of Yunnan, China, have discovered an extraordinary giant fungus”
- SupportedDianjunus rex can reach 50 centimetres tall and weigh up to 2.2 kilograms.Latest Science News -- ScienceDaily: “The newly identified species, Dianjunus rex, produces upright reproductive structures that can reach 50 cm (20 inches) in height and weigh as much as 2.2 kg (4.9 pounds).”
- SupportedIts fruiting bodies are the largest known among ascomycete fungi.Latest Science News -- ScienceDaily: “These are the largest known fruiting bodies among fungi belonging to the phylum Ascomycota.”
- SupportedThe Dianjunaceae lineage originated about 65 million years ago, roughly one million years after the Cretaceous-Paleogene mass extinction.Latest Science News -- ScienceDaily: “Their results suggest that the lineage originated approximately 65 million years ago, roughly one million years after the Cretaceous-Paleogene mass extinction.”
- SupportedSenanayake said: “This remarkable species represents a new fungal family, Dianjunaceae, and provides a rare window into the evolution of extreme fungal body forms.”Latest Science News -- ScienceDaily: “"This remarkable species represents a new fungal family, Dianjunaceae, and provides a rare window into the evolution of extreme fungal body forms," said Dr Indunil C Senanayake”
- SupportedResearchers surveyed temperate coniferous forests near Damaidi and Yipinglang and tropical rainforest near Nanbang in Yunnan.Latest Science News -- ScienceDaily: “Their fieldwork included temperate coniferous forests near Damaidi and Yipinglang, along with tropical rainforest near Nanbang.”
- SupportedThe team observed whitish stromata growing from the woody roots of Chinese cork oak trees.Latest Science News -- ScienceDaily: “The team spotted unusually large, whitish reproductive structures, known as 'stromata', growing from the woody roots of Chinese cork oak trees.”
- SupportedThe fungus was identified as a new species, a new genus and a new family, Dianjunaceae, within the order Xylariales.Latest Science News -- ScienceDaily: “It was sufficiently different from known fungi to require the creation of a new genus and an entirely new family (Dianjunaceae) within the order Xylariales.”
- Partly supportedThe fungus uses enzymes to decompose dead wood and obtain nutrients.Latest Science News -- ScienceDaily: “Researchers believe similar enzymes may allow 'D-rex' to decompose dead wood and obtain nutrients from it.”
- SupportedSenanayake said: “After the mass extinction, forests experienced dramatic changes, including the sudden availability of large amounts of dead plant material.”Latest Science News -- ScienceDaily: “"This timing raises an intriguing possibility. After the mass extinction, forests experienced dramatic changes, including the sudden availability of large amounts of dead plant material," said Senanayake.”
- SupportedBefore this discovery, the tallest known ascomycete fruiting bodies measured about 20 to 30 centimetres.Latest Science News -- ScienceDaily: “Before its discovery, the tallest known ascomycete fruiting bodies measured approximately 20 to 30 cm.”
- SupportedSenanayake hypothesised: “A fruiting body which towers above surrounding vegetation and debris could have better dispersal of spores by wind in dense forests. However, such a large structure requires substantial energy investment, suggesting that this strategy likely evolved only where the ecological benefits outweighed the costs.”Latest Science News -- ScienceDaily: “"A fruiting body which towers above surrounding vegetation and debris could have better dispersal of spores by wind in dense forests. However, such a large structure requires substantial energy investment, suggesting that this strategy likely evolved only where the ecological benefits outweighed the costs," hypothesized Senanayake.”