Dennis Desjardin: A fungus named after SpongeBob
A newly identified mushroom species named after SpongeBob Squarepants caught our eye and led EarthSky’s Emily Willingham to contact Dennis Desjardin, the scientist who discovered the genus. The mushroom, a native of Borneo, is Spongiforma squarepantsii, one of only two known members of the Spongiforma genus. Its sea-sponge shape inspired its name, which is probably better than any name motivated by its “vaguely fruity or strongly musty” odor. That descriptive comes courtesy of Dennis Desjardin, a professor at San Francisco State University, intrepid fungus hunter, discoverer of the Spongiforma genus, and one of the people to happily blame for naming a mushroom after a cartoon character. He is an author on what is likely the only scientific paper ever to include the following:
Named in honor of the famed cartoon character SpongeBob SquarePants, whose sponge shape shares a strong resemblance to the new fungus. Moreover, the hymenium when observed with scanning electron microscopy (FIG. 3) looks like a seafloor covered with tube sponges, reminiscent of the fictitious home of SpongeBob.
See? Science is fun, and at the end of this interview, you’ll see that Dr. Desjardin is not only a biologist but also a man with a bit of the poet about him.
Can you tell us a little bit about how you came across this mushroom?
The species was discovered by my co-authors Tom Bruns and Kabir Peay while they were conducting a research project on ectomycorrhizal mushrooms of Borneo. They collected mushrooms from under the trees they were sampling to compare their DNA with that on the roots to see if they were mutualistically associated with the trees (involved in a mutually beneficial relationship).
Was it recognized right away as an undocumented species?
When they encountered this particular species, they were surprised at first and had no idea what it was. After returning to the U.S., Tom Bruns contacted me and asked if it looked familiar, and was maybe related to the new genus I had just described from material collected in Thailand, Spongiforma thailandica. I said yes, it was related, and we compared their DNA sequences to the ones I had for S. thailandica. Lo and behold, they were sister species. Now the genus has two species, one from Thailand and one from Borneo.
What is it like to comb unexplored forests for mushrooms? I’m guessing it’s not all glamour and excitement.
It is a fantastic job. I currently have active projects in Thailand, Malaysia, Indonesia, Micronesia, Hawaii, Brazil, Sao Tome and Principe, and California. It is a lot of work, requires good logistics and collaborations with local governments, scientists and students, and it has its dangers … like jaguar, gaur (bison native to Asia), viperous snakes, leeches, necrotic spiders.
But we often find really exciting new organisms that create a buzz with the public. Check out the website for the International Institute for Species Exploration. We made their Top 10 New Species list two years in a row. For 2010, with Phallus drewesii (a small penis-shaped mushroom only 2 inches long that droops down, that I named after a colleague!) from Africa, and this year, 2011, with Mycena luxaeterna, a bioluminescent (glowing) mushroom from south of Sao Paulo, Brazil.
Is there a way (besides the obvious) to determine if a mushroom like this one is edible?
NO. We can test for the presence or absence of specific poisonous compounds, but if they are absent that does not mean the species is edible. It could very easily have poisonous compounds that we did not test for. We can make educated guesses. For example, if the species belongs to a lineage of mushrooms where all of the other species with known edibility are poisonous, we’d suggest to not eat it!
Editor’s Note: The Spongebob mushroom happens to be pretty closely related to porcini mushrooms, which are edible. But it’s not your regular sort of mushroom. For one thing, it doesn’t have that cap-and-stem design and looks like a sponge. In fact, according to a quote from Desjardin in a news release about Spongiforma squarepantsii, “It’s just like a sponge with these big hollow holes. When it’s wet and moist and fresh, you can wring water out of it and it will spring back to its original size. Most mushrooms don’t do that.”
What is the other species in the Spongiforma genus? How does it compare to its partner in the genus?
The other species is Spongiforma thailandica, and it compares with S. squarepantsii by the features outlined in the paper.
Editor’s Note: I looked at the paper as directed and found, among other things, that odor might be related to animal attraction for both species. The attracted animals, in turn, would aid in dispersing spores, the fungus version of seeds. What makes them different? Some important similarities – and differences – at the DNA level and some differences that are more obvious to regular folk. For one thing, the Thai species, instead of having a fruity or musty odor, smells like “coal tar,” and the two species differ in color and size.
In the news release about this latest species, you mention that a good-sized percentage of what you find is new to science. Does it remain exciting to discover a new species with this level of frequency, and how do you go about determining new species names (besides the obvious for the Spongiforma squarepantsii)?
Yes, it is always a thrill to find and describe a new species, but it is a tremendous amount of work to prove that what you have represents a new species. First of all, you need to know the features of every other species described in the genus to which your unknown belongs, and then you have to compare your material to all of the other species. If it has different morphology (form) and molecular characters (such as DNA), then you can provide data to support your supposition that it is new to science. With contemporary techniques, we can sequence several genes and compare them to those of morphologically similar species and then interpret the results.
As far as naming goes, I usually use a descriptive name for new species, and I often use the native language of the country where the species occurs. For example, in Hawaii, for a beautiful pink mushroom that grows in the wet native forests, I chose the species name Hygrocybe noelokelani, which means “the pink rose in the mist” in Hawaiian; and for a species with a really gelatinous cap and stem I called it Hygrocybe pakelo, which means “slippery like a fish.” In Thailand, I chose Crinipellis tabtim for a ruby-red species because tabtim means “ruby-colored” in Thai. In Malaysia I chose Marasmius iras which means “resembling” in Malaysian because it is reminiscent of another species from the same area. But usually we use Latin names that are adjectives, like atrobrunnea (dark brown), cupreostipes (with copper-colored stem), or angustilamellatus (narrow gilled).
Editor’s Note: And then sometimes, they turn to a famous cartoon sponge.