The Dinosaurs Moved Out. A Fungus Named Rex Moved In.

Out of the soil around dead trees in China's Yunnan province rises a fungus that can stand 50 centimeters (about 20 inches) tall. One specimen tipped the scales at 2.2 kilograms, close to 5 pounds. Science had no family to put it in, so it got a brand-new one.

Yu Fuqiang's team at Kunming Institute of Botany, a Chinese Academy of Sciences institute, collected specimens in Yunnan's tropical and subtropical woodlands from August 2024 through July 2025. They named the species Dianjunus rex and created the family Dianjunaceae to hold it, in Frontiers in Fungal Biology.

These fungi grow 20 to 50 centimeters (8 to 20 inches) tall, thick and upright, with rounded heads that sprout fingerlike branches as they age. Most weighed 250 to 600 grams (roughly 9 ounces to 1.3 pounds). The heavyweight carried the biggest spore-making body ever documented in Ascomycota, a major branch of the fungal family tree.

Dianjunus nods to Yunnan's ancient Dian Kingdom plus the Chinese term for fungus. Rex is Latin for king, the title Tyrannosaurus wears, a wink at the size.

The dinosaur link goes deeper. The team traced the family back roughly 65 million years, to just after the extinction that ended the non-avian dinosaurs, when ecosystems were still rebuilding.

Why so big? The researchers offer an unconfirmed idea. The fungus may live inside healthy trees, then switch to eating dead plant matter once its host is gone, freeing resources for those outsized spore structures.

Scientists have recorded over 6,000 kinds of fungi in Yunnan and estimate the province may hold more than 100,000.

The king has been crowned. Most of the court is still hiding in the leaf litter.

Read the full story at Chinese Academy of Sciences, October 16, 2026

Hot Take: Moving in with a healthy host and maybe inheriting the estate is a bold housing plan. Our compost gets the same dead wood and has yet to grow a king.