Continuing our march through the Top 10 Open Access Fossil Taxa of 2017…
We’re now in the top five, as determined by popular vote. Tied for fourth/fifth place, we have the mighty Gondwanagaricites magnificus. It’s not a ferocious dinosaur. It’s not a fish. It’s not even a vertebrate, but I would argue it’s way cooler–it’s the current record holder for the oldest fossil mushroom!
Fungi had to have diverged from other organisms nearly a billion and a half years ago (based on genetic evidence and fossil records of non-fungi), and fossil fungal spores aren’t unheard of in the fossil record. But, the mushrooms we most often think of (gilled mushrooms, or Agaricales) are pretty rare as fossils. Their distinctive fruiting bodies, represented by “toadstools” on the lawn, portobello on the grill, and the topping on the half of the pizza insisted upon by your friend because they know nobody else will eat it when there’s pepperoni available–don’t fossilize easily, and fewer than a dozen examples have been described in the literature, all trapped within amber. The previous world champ (or champignon, for the Francophiles) was “only” 99 million years old.
Our new champignon/champion dates back to around 115 million years ago, recovered in fine-grained limestones from Brazil. These same rocks have produced exquisitely preserved flying reptiles, birds, insects, fish, and other fossils, and now a mushroom! This occurrence is pretty surprising, not so much for the age (similar mushrooms must have existed well before then, even if we haven’t found them yet), but for the unusual environment. The Crato Formation where the mushroom originated represents shallow marine conditions. This isn’t exactly a typical habitat for mushrooms, so it’s likely that the ‘shroom was washed out from the nearby lands (consistent with some other terrestrial plants and animals in the same deposits).
Who knows what other mushrooms are lurking out there in the fossil record? Gondwanagaricites certainly gives us incentive to keep looking!
Heads SW, Miller AN, Crane JL, Thomas MJ, Ruffatto DM, Methven AS, et al. (2017) The oldest fossil mushroom. PLoS ONE 12(6): e0178327. https://doi.org/10.1371/journal.pone.0178327