Giant Fungus 'D-Rex' Gets Its Own Family in China

A giant fungus nicknamed D-rex just forced scientists to build a brand-new branch on the tree of life. Found in the forests of Yunnan, China, Dianjunus rex grows fruiting bodies up to half a metre tall, and it is so different from its relatives that researchers gave it an entire family of its own.

What exactly did they find?

The discovery comes from the Kunming Institute of Botany, part of the Chinese Academy of Sciences. According to the Chinese Academy of Sciences, the team collected specimens from tropical and subtropical forests in Yunnan between August of twenty twenty-four and July of twenty twenty-five. The fungi were growing from the roots of recently dead trees and the soil around them.

Each fruiting body stands between twenty and fifty centimetres tall, counting a buried stalk, with thick upright columns and rounded tops. Most specimens weighed between two hundred fifty and six hundred grams, but one double-lobed monster tipped the scales at two point two kilograms. That is roughly the weight of a small laptop bag, except it grew out of the ground.

As the fungus ages, those pale rounded tops darken and split into narrow, finger-like branches that release spores. The researchers say it is the largest fruiting structure ever recorded in the Ascomycota, the biggest fungal group on Earth, which includes morels, truffles and the zombie-ant fungus cordyceps.

Why one giant fungus needed its own family

Size was only part of the story. After DNA and microscope work, the team concluded the fungus was not just a new species. It also needed a new genus, Dianjunus, and a new family, Dianjunaceae, inside the order Xylariales. For now that family has exactly one member.

The name is a nod to history and pop culture. "Dian" refers to the ancient Dian Kingdom that once stood in Yunnan, while "jun" is the Chinese word for fungus. The Latin word rex means king, and yes, the team clearly enjoyed the echo of T. rex. Until now, the record holders in this lineage topped out at twenty to thirty centimetres, about half of D-rex.

A lineage that goes back to the dinosaurs' downfall

A molecular clock analysis, which uses the pace of genetic mutations to date when species split from a common ancestor, traces the family back about sixty-five million years. According to Discover Wildlife, that is only one million years after the asteroid-driven mass extinction that wiped out the non-avian dinosaurs.

Corresponding author Indunil Senanayake said the species "provides a rare window into the evolution of extreme fungal body forms." His hypothesis is that after the extinction, forests were suddenly full of dead plant material, which created new openings for wood-decaying fungi. A tall fruiting body poking above the vegetation could catch the wind and spread spores farther in dense forest.

Building something that big costs a lot of energy, so the team thinks the strategy only evolved where the payoff beat the price. As ScienceAlert notes, the fungus is often found at the base of oak trees, including the Chinese cork oak.

Why this matters beyond the memes

Yunnan is already a global fungus hotspot. Discover Wildlife reports more than six thousand species have been documented there, yet scientists estimate over one hundred thousand are still hiding in its ecosystems. If a half-metre fungus could go unnoticed, imagine what is still out there.

Members of the Xylariales are known for making unusual chemical compounds and enzymes that break down tough plant material. That makes them interesting for biotechnology and the search for natural products, from greener industrial processes to new drug leads. Nobody has tested D-rex for any of that yet, so treat those ideas as possibilities rather than promises.

The findings are published in the journal Frontiers in Fungal Biology. For a generation that grew up on dinosaur memes and nature documentaries, a giant fungus born in the dinosaurs' aftermath is a pretty perfect mix. More science stories live on our science page, and this is one worth watching as researchers dig into what D-rex can do.