In January, Lohit Y.T., a river and wetlands specialist at World Wildlife Fund-India, shared his discovery of Rao’s intermediate golden-backed frogs in a roadside pond with tiny bonnet mushrooms growing from their flanks in the journal Reptiles and Amphibians. After posting pictures of the frog online, citizen scientists and mycologists identified the fungal hitchhiker as a bonnet mushroom. This type of mushroom typically grows on decaying plant matter, not living animals, which raises questions about how it ended up on the living frog.
The growth of a mushroom requires a fungal spore to establish itself and produce mycelia, threadlike cells that absorb nutrients. This process usually occurs on a surface and, in the case of living creatures, raises questions about whether the mycelia are on the skin or inside the amphibian’s body. Although scientists have come across fungi in unusual places before, finding a living mushroom on an animal is unprecedented. Matthew Smith, a fungal biologist at the University of Florida, expressed surprise at the discovery but noted the absence of a collected specimen limits further analysis.