Doff Your Hat to this Fungus from Malaysia! - Observation of the Week, 8/6/24

Our Observation of the Week is this Praearthromyces corneri fungus, seen in Malaysia by @gim-siew_tan!

Gim Siew Tan is a remarkable fungus and slime mold photographer who hails from Malaysia. She enjoys hiking and “taking in the beauty of the outdoors,” and started noticing many of the fungi living in the forests. Starting her photography hobby with her smartphone, she now “specialize[s] in extreme macro photography, especially with slime molds, and as a citizen scientist.”

Across her many hikes, she has come across Praearthromyces corneri before, in 2023, but says

I wasn't expecting to see it in this nearby forest park that I frequent. With the distinctive gill shape and concave, shallow depression in the cap, this species is really lovely. I intended to capture the mushroom's attachment of some parts to the leaves in its natural environment since I considered that to be quite interesting.

Praearthromyces corneri was described back in 2022 and, iNat being the amazing community it is, one of the paper’s coauthors, @lennartvdpeppel, commented on Gim Siew Tan’s post and was kind enough to write a few paragraphs about it for us. 

The mushroom of Praearthromyces corneri is easy to recognize in the field because of its typical cup-shaped cap with black, gray and white zones. In the dark zones, chains of asexual spores (called arthroconidia) are produced (a trait that is very rare in mushroom-forming fungi!). Another typical feature of this mushroom is the long rooting stipe (called a pseudorhiza). This species shows resemblance to a species described by the British mycologist E.J.H. Corner. However, we could not confirm whether it is the exact same species, therefore we described it as a new species but named it after Corner. 

Praearthromyces corneri is part of an interesting group of fungi, some of which are associated with insects. By sequencing the DNA of several different species, we found that the genus Praearthomyces is closely related to the neotropical genus Arthromyces. Both Praearthomyces and Arthromyces are closely related to the genus Termitomyces, which is cultivated by termites. The termites grow Termitomyces fungi in their nest as a source of food. Like P. corneri, species of Arthromyces also have a rooting stipe. We discovered that when we carefully dug out the rooting stipe of Arthromyces, it was attached to a mass of insect fecal pellets. Since Arthromyces and Termitomyces are both associated with insects and share several other traits, including the rooting stipe, we concluded that their common ancestor must have been predisposed towards domestication by termites. 

We have not been able to confirm an insect-association for P. corneri yet. But since it produces asexual spores and has the rooting stipe, we are pretty sure it also grows on insect poop. In case anyone of the iNaturalist community observes this fungus again, make sure to carefully dig out the rooting stipe and take some photos of the insect pellets in case they are there.

Gim Siew Tan (above, in China) came across iNaturalist back in 2021, and tells me

I use it mainly as a citizen scientist to document the slime molds and mushrooms that I find in Malaysia. Also, there isn't much information available with regard to slime molds in Malaysia; thus, iNat is an ideal place for me to establish a database. I've since become a slower hiker, becoming more aware of my surroundings, and enjoying the smaller things in life and whatever I may discover as I pass by.

(Photo of Gim Siew Tan taken by CS Cheah. Some quotes have been lightly edited for clarity.)

- check out Gim Siew Tan’s Instagram page!

- this observation of beetle-related fungus by @cgmayers was an Observation of the Day last year!

- is it just me, or do these mushroom photos remind you of the opening shot of The Prestige?

Posted on August 6, 2024 10:45 PM by tiwane