Once upon a time, long before soil-dwelling plants and complex life, fungi ruled the land.
Scientists have found the oldest confirmed evidence of fungi on Earth. According to a new study published in Science Advances, fossilized specimens clearly show that fungi lived on Earth between 715 and 810 million years ago, a colossal 300 million years earlier than previously thought.
This discovery is about much more than just mushrooms. Considering fungi have played a crucial role in the evolution of other lifeforms on Earth, the fossils could hold a number of big implications.
"This is a major discovery, and one that prompts us to reconsider our timeline of the evolution of organisms on Earth," Steeve Bonneville, professor at the Université libre de Bruxelles and coordinator of the study, said in a statement. "The next step will be to look further back in time, in even more ancient rocks, for evidence of those microorganisms that are truly at the origins of the animal kingdom."
Researchers from Université libre de Bruxelles came across the discovery while studying rock specimens at the Royal Museum for Central Africa in Belgium. Within one of the ancient rocks, they discovered the presence of a microscopic network of filaments. An array of different advanced microscopy techniques showed that these filaments were mycelium made out of chitin, a tough compound found in the cell walls of fungi.
A study last year claimed to have found fossil fungi that dated back to somewhere between 900 million and 1 billion years ago, however, the chitin in this specimen was not molecularly identified and its veracity is not totally confirmed.
The recently studied fungi fossil most likely grew in a lagoon or coastal lake environment in what’s now the Democratic Republic of the Congo, Central Africa. Based on this location, the team argue that the fungi might have played a key role in supporting the first plants that colonized the Earth's surface around 500 million years ago.
Fungi are deeply interconnected with other forms of life and were the vital architects of the modern-day ecosystem. They are part of an underground network of microbes that help to keep soil in check. As decomposers and recyclers, they make it possible for other life forms, whether that’s plants or animals, to be supplied with nutrients that would otherwise be impossible to harness.
Considering the microfossil was alive almost 300 million years before the first evidence of land plants, it further affirms the idea that fungi were most likely colonizing the land before plants, preparing the Earth for their arrival.
“The presence of fungi in this transitional area between water and land leads us to believe that these microscopic mushrooms were important partners of the first plants that colonized the Earth's surface around 500 million years ago," explained Bonneville.