Ancient Fungus as Tall as a Traffic Cone Has Just Been Discovered in China

Yunnan Province in China is famous for its mushrooms and fungi, but somehow, scientists have only just come across a new species that has rightly earned the name 'king'.

Named Dianjunus rex (or D. rex for short), its gigantic, club-like fruiting bodies can grow up to 50 centimeters tall, which is about one and a half feet, or the height of a traffic cone.

But its impressive size is not the only exciting thing about this fungus. Its genes also contain clues about a major moment in the history of life on Earth.

Mycologist Indunil Senanayake of the Chinese Academy of Sciences and her colleagues describe the new species in a paper published in Frontiers in Fungal Biology.

D. rex is the only known member of its family, Dianjunaceae.

"This remarkable species… provides a rare window into the evolution of extreme fungal body forms," says Senanayake.

"The discovery illustrates how much fungus biodiversity remains to be discovered in East Asian forests."

The researchers found the Dianjunaceae family split off from its closest known relatives about 65 million years ago, by comparing its DNA to hundreds of other fungi whose evolutionary history is well-known.

"This timing raises an intriguing possibility," says Senanayake.

The family emerged just 1 million years after the Chicxulub asteroid impact, which triggered a mass extinction event.

The dramatic changes to Earth's climate that resulted from the asteroid wiped out three-quarters of plant and animal species on Earth, including, famously, all non-avian dinosaurs.

"After the mass extinction, forests experienced dramatic changes, including the sudden availability of large amounts of dead plant material," Senanayake says.

"For wood-associated decomposing fungi, such environmental disruption may have created new ecological opportunities."

This isn't the first time scientists have proposed that the dinosaur-killing asteroid led to a worldwide fungal 'boom'. Fossils found in North Dakota, Colorado, and New Zealand show that massive spikes in fungal activity followed in the wake of this mass extinction.

Fungi typically prefer cooler temperatures and acidic environments. The cooler and darker conditions that arise when geological calamities shade our skies – as Chicxulub did – could have easily set the scene for an era dominated by fungi.

D. rex is related to fungi like morels, truffles, and cordyceps, in the phylum Ascomycota. Like all fungi, Ascomycetes live as mycelium, below the ground or inside the substrates (wood, poop, your toenails, etc.) upon which they feed.

D. rex is often found at the base of oak trees, including the Chinese cork oak (Quercus variabilis) in the forests of the Yunnan Province in south-western China. The specimens on record so far were growing on the decaying roots or stumps of these trees.

When it comes time to reproduce, D. rex sends out its gigantic white fruiting bodies, which are called stromata. These serve the same purpose as mushrooms do for other fungi, broadcasting spores into the air so more D. rex may flourish on the forest floor.

But it's unclear why D. rex's stromata are quite so gargantuan – the largest of any Ascomycete on record. Some specimens the researchers collected weighed a whopping 2.2 kilograms.

"A fruiting body which towers above surrounding vegetation and debris could have better dispersal of spores by wind in dense forests," Senanayake proposes.

"However, such a large structure requires substantial energy investment, suggesting that this strategy likely evolved only where the ecological benefits outweighed the costs."

The research has been published in Frontiers in Fungal Biology.