First mushroom growing on living animal tissue

On 19 June 2023, a Rao's intermediate golden-backed frog (Hylarana intermedia) with what appeared to be the fruiting body of a bonnet mushroom (Mycena spp.) attached to its side, was sighted in Mala, near Karkala, Karnataka, India. This is believed to be the first time that a mushroom (specifically the sporocarp/fruitbody structure of a fungus) has been recorded living on the skin of a live animal. The herpetological survey in the rainforest-covered Western Ghats mountains was conducted by naturalists Chinmay C Maliye, Naveen Iyer, Nisha BG, Asha S, Afran and Lohit YT (the latter of the WWF-India); they reported on their unusual discovery in the journal Reptiles & Amphibians on 28 January 2024.

It's worth noting that this is not the first example of fungi growing on living animal tissue; indeed, there is a very common fungal infection caused by Batrachochytrium dendrobatidis, causing the deadly disease chytridiomycosis, that has affected more than 700 species of amphibians. Similarly there is another fungus (Pseudogymnoascus destructans) which causes a condition called "white nose syndrome" on certain species of bat. There are also examples in humans, including the common condition athlete's foot (Tinea pedis) and one case of the mould Schizophyllum commune growing in the nasal passages of a 50-year-old woman. But in all these cases, the fungi do not produce sporocarps (mushrooms) to release their spores, which is what makes this case unique.

In many cases of fungi that live on the bodies of living animals, the organisms are pathogenic. In some cases, such as Cordyceps and Ophiocordyceps, they can even hijack the brains of their insect hosts to make them behave unnaturally (ultimately to their self-destruction) – a phenomenon that has given rise to the concept of "zombie bugs". In the case of this frog, it did not seem as if the fungus was affecting its health, but of course this can not be proven from a few photos and brief observation.

For some mycologists further research is needed before any conclusions on this unprecedented case can be drawn, because as the naturalists were only on an observational survey, the frog was not collected for scrutiny; as a result the precise species of fungus and how it had come to grow on the frog's skin remain unknown. The most sceptical have even queried if the growth was indeed a fungus, though there is considerable consensus that it very much looks to be a bonnet mushroom.