Scientists discover 'D-rex', a giant fungus from Chinese forests whose unique lineage dates back 65 million years

In the deep forests of Yunnan, China, scientists have uncovered a giant fungus named Dianjunus rex. This species is remarkable for its vertical fruiting bodies, which can reach up to 50 cm (20 inches) in height and weigh as much as 2.2 kg (4.9 pounds). These are the largest known fruiting bodies within the phylum Ascomycota. Dianjunus rex represents a new fungal family, Dianjunaceae, and offers a unique glimpse into the evolution of extreme fungal body forms, according to Dr. Indunil C. Senanayake, the corresponding author of the study published in Frontiers in Fungal Biology.

The discovery highlights the vast potential for fungal biodiversity still undiscovered in the forests of East Asia. During fieldwork in temperate coniferous forests near Damaidi and Yipinglang, and in tropical rainforest near Nanbang, researchers from the Kunming Institute of Botany found large whitish fruiting bodies belonging to an unknown ascomycete fungus.

These grew on the roots of Chinese cork oak, emerging from the rhizosphere. Genetic and morphological analyses reveal that Dianjunus rex is a new species, genus, and even a new family within the order Xylariales. Molecular dating estimates that this lineage originated around 65 million years ago, coinciding with the Cretaceous-Paleogene mass extinction event.

This timing suggests that the dramatic changes in forests following the mass extinction, including the sudden availability of large amounts of dead plant material, may have provided new ecological opportunities for wood-associated decomposing fungi like Dianjunus rex.