As the Age of Dinosaurs collapsed about 65 million years ago, a new species rose from the ruins: a king of the fungi world.
Scientists recently identified a huge species of fungus in the region that makes up China today, and named it Dianjunus rex, which shares part of it with the famous Tyrannosaurus rex, nicknamed the "king" of the dinosaurs.
Diangonus rex, or D. rex for short, belongs to a family of fungi that emerged following the extinction event that wiped out all non-avian dinosaurs, along with about 75% of plant and animal life on Earth.
D. rex is larger than other fungi, with reproductive structures (known as “fruiting bodies” or “stromes”) that are pale yellow in color and extend vertically, and can reach 50 centimeters in length.
This is approximately the height of a small suitcase intended for airplane cabins, and its weight is approximately 2.2 kilograms.
“It is always exciting to learn about a new species of fungus that is distinguished by its enormous size,” says Kabir Bai, a professor of biology and Earth system sciences at Stanford University in California, who was not involved in this research. “This highlights the existence of unique forms of wildlife on our planet that science has not yet had the opportunity to describe.”
Scientists spotted this fungus in the forests of Yunnan Province, southwest China, during fungal diversity surveys conducted in 2024 and 2025.
The results were published September 28 in the journal Frontiers in Fungal Biology.
Farmers in the area had previously noticed these fleshy, finger-like fungal structures clustered around a dead tree.
According to Indunil Senanayake, an associate professor at the Kunming Institute of Botany in China and a co-author of the study, some local residents have tasted this huge mushroom and did not show any harmful effects, even though it has not yet been tested for toxins.
“No one noticed the importance of this mushroom,” Senanayake told CNN in an email.
But when a curious local resident sent photos of this strange mushroom to scientists, the researchers immediately knew they had a special discovery.
The study indicates that the mass extinction that wiped out the dinosaurs may have created a suitable environment for this huge fungus to evolve and flourish.
D. rex is not only a newly discovered species, it also belongs to a unique family of fungi.
Through genetic analysis and comparisons with other fungi, the researchers found that this new family, which they called Dianjunaceae, likely appeared about a million years after the asteroid impact that ended the Cretaceous period (145 million to 66 million years ago).
“During this event, photosynthesis stopped, and huge amounts of dead leaves, wood, roots and corpses of organisms accumulated,” Senanayake explained.
At a time when other life forms were struggling to survive, decomposers, such as fungi that feed on dead organic matter, were able to take advantage of the available food.
Although D. rex is not the same size as T. rex, it is larger than many other types of fungi.
This is the largest known species within the phylum Ascomycota, which is the most diverse group of fungi, containing about 65 thousand species.
Senanayake adds that before the discovery of D. rex, the largest known member of this phylum was a brown bulbous fungus found in Kenya known as Engleromyces goetzei.
Its diameter is approximately 30 centimeters and its weight is approximately 3.2 kilograms.
Senanayake points out that one of the questions that scientists seek to answer in the future is: Why is D. rex so large compared to other fungi in the same phylum?
“In general, these fungi do not produce large fruiting bodies, because that is a waste of energy,” she explained.
These fungi reproduce by extruding their spores, and in the case of D. rex, the upper part of the fruiting bodies contains thousands of tiny pores dedicated to releasing spores.
According to Senanayake, the forest floor in the habitats of this fungus is densely covered with fibrous plant material that may hinder the spread of spores.
It is likely that the height of the fruiting body of D. rex above the forest floor may help spread the spores more widely, which enhances the chances of successful reproduction.
Fungi are essential organisms that contribute to the planet's carbon cycle and support the health and nutrition of many plant species.
Bai emphasized: “It is important to understand the roles that these organisms play. The first step towards this begins with describing them and acknowledging their existence, and then seeking to understand deeper details about their nature.”
So far, scientists have been able to describe about 150,000 species of fungi, while some estimates indicate that there are between 2 million and 13 million species on Earth.
“It's a group of organisms that is underappreciated, understudied and underdescribed,” Bai adds.
