The Fascinatingly Fortuitous Fossilization of Farts
There are people out there who don’t think palaeontology is astonishing, and they are quite wrong. To prove this, here is a 20 million-year-old cockroach fart, fossilized in amber:
The late lamented Dr WHO once told me “serendipity is looking for a needle in a haystack and finding the famer’s daughter.” I think my version is now “looking for an expert on fungal nodules and finding the world’s oldest fossilized fart.”
It began on Twitter, where Stuart Petch sent myself and Paolo Viscardi an Instagram image of his friend Harry’s lump of amber, wondering if the white blobs in it might be fungus nodules. It meant nothing to me, but my dear friend Dr Leyla Seyfullah at the University of Vienna is an expert on fossil plants, fungi, and amber, so I Facebooked her for her thoughts.
Meanwhile, Paolo asked his friend Lee Davies, a mycologist at Kew, if he had any advice. After a bit of searching, Lee said that the oldest example of a fungal farm he could find was about 25 million years old, which was quite exciting, as this piece of Baltic amber was up to* 20 million years older!
Over on Facebook, though, Leyla was swift to reply, and this cranked my excitement levels up to 11. “Termites eat dead plants,” she said. “To be able to digest dead plants, you need masses of gut microbiota. As the dead plants are digested by the gut microbiota, gases are produced. What you are seeing are lots of termites with clear fossilized farts…”
Sorry, hold your fossilized termites one moment, Dr Seyfullah. Did you just say FOSSILIZED FARTS?
“…as their gut microbiota kept breaking down food after the termites got stuck in the resin. Sometimes the termites ripped themselves a bit as they struggled in the sticky resin, so the gases escaped through any exit out of the termite.”
She added that, despite termites being ‘notoriously gassy’ not *all* the bubbles were of digestive origin (plenty could just be trapped air bubbles), but by that point I was miles away, in paroxysms of resinated guffery, searching for ‘fossilized farts‘ on Google.
Reader, I found some, in a chapter by George Poinar in the Fossil Behavior Compendium he wrote with Art Boucot in 2011. They are from the amber deposits of the Dominican Republic, which Poinar has studied in great detail and which Seyfullah et al. (2018) describe as being 16 to 18 million years old.
Melissa Stewart’s Blasts of Gas then mentioned that Lynn Margulis had analysed the chemistry of fossil termite farts in 2002, so I had to dig out that scientific paper. ‘Spirochete and protist symbionts of a termite (Mastotermes electrodominicus) in Miocene amber’ by Wier et al. (2002) focusses primarily on the micro-organisms preserved in the termite’s gut. The Dominican amber fossilization is exceptional, extraordinary.
The authors do, however, mention that the amber termites are ‘invariably preserved with bubbles that emanate from thoracic or abdominal spiracles’ and that the bubbles contain ethylene, methane, and carbon dioxide.
“We propose that these gases were generated in large quantity by the unique hindgut microbial community, and exuded as the insect was immersed in the viscous resin” (Wier et al., 2002). I never doubted Leyla for a moment, of course, but it’s always handy to have a precedent: fossil farts from a 16-18 million year-old termite!
But yes, it’s only 16 to 18 million years old. The Baltic amber termites are at least 7 million years older, and more likely at least 16 million years older. The oldest fossil fungal farm? The oldest termite ? The oldest fossil fart? The possibilities are effervescent.
In conclusion, a Facebook reply to a Twitter post about an Instagram photo confirms that palaeontologists should definitely use social media, because the most amazing things can bubble up as a consequence. I just wish I’d know about fossil farts when I wrote this article for the Conversation.
*according to Kettunen et al. (2018), Baltic amber can be between 25 and 43 million years old, whilst Seyfullah et al. (2018) state that it is 34-48 million years old, so there’s quite a lot of potential variation in this figure. Such are the joys of biostratigraphy.