The world's oldest mushroom fossil was discovered in a piece of ancient limestone in Brazil. Photo by Sam Heads, et al./PLOS ONE
June 7 (UPI) -- Some paleontologists look for dinosaur bones. Others look for mushrooms. And one of those fungus hunters, a paleontologist from the University of Illinois, has discovered the oldest fossil mushroom in the world.
The 115-million-year-old fossil was discovered in the limestone in Brazil. The mineralized mushroom hails from a time when all of the world's continents formed a single piece of land called Pangea.
Scientists believe the mushroom became unanchored and swept away by a river on the ancient supercontinent, ending up in an extremely salty lagoon. As sediments piled up in the lagoon and the briny water evaporated, a variety of organic matter -- including this mushroom and others -- became trapped and preserved.
Over time, the mushroom's tissue was replaced with pyrite, or fool's gold. The fools gold eventually became goethite, an iron bearing hydroxide mineral.
"Most mushrooms grow and are gone within a few days," Sam Heads, a paleontologist with the Illinois Natural History Survey, said in a news release. "The fact that this mushroom was preserved at all is just astonishing."
Heads found the mushroom while excavating fossils from Brazil's Crato Formation. He dubbed the gilled species Gondwanagaricites magnificus.
"When you think about it, the chances of this thing being here -- the hurdles it had to overcome to get from where it was growing into the lagoon, be mineralized and preserved for 115 million years -- have to be minuscule," he said.
Heads described his discovery in the journal PLOS ONE.
Prior to Heads' discovery, the oldest known mushroom fossil was a 99-million-year-old specimen trapped in amber. It was discovered by mycologist Andrew Miller in Southeast Asia.
Mushrooms played an important role in helping plants make the transition from sea to dry land.
"Fungi evolved before land plants and are responsible for the transition of plants from an aquatic to a terrestrial environment," Miller said. "Associations formed between the fungal hyphae and plant roots. The fungi shuttled water and nutrients to the plants, which enabled land plants to adapt to a dry, nutrient-poor soil, and the plants fed sugars to the fungi through photosynthesis. This association still exists today."