In fossils unearthed from the Canadian Arctic, scientists discovered billion-year-old fungus that could reshape human understanding of ancient life on Earth.
Fungi hold an important place in the ecosystem as they decompose organic matter and release nutrients to help life grow on Earth. Not only do their fossils reveal valuable insights about the evolution of life, but they are some of the most abundant organisms on Earth with six times the biomass than all other animals combined, including humans.
So, since these ancient microfossils are dated to a billion years ago, it not only reveals that fungi originated more than half a billion years earlier than previously believed, but also that the landscape back then is probably more complex than scientists originally imagined. If fungi existed a billion years in the past, animals may have emerged already as well.
The Fungi Dilemma
While previous research have suggested that fungi emerged much earlier than animals, there's a scarcity of concrete evidence of fungus existing prior to the Cambrian Period's explosion of life about 541 million years ago. Scientists have found a handful of fungus-like fossils from about 600 million years ago, but there's limited evidence to definitively conclude these are actually fungi.
For the last few decades, the earliest known unambiguous fungi are roughly 410 to 450 million years old. However, new findings of a study published in the journal Nature reveal that the recent microfossils found in Canada are much older at between 900 million and 1 billion years old.
By using precision-imaging techniques such as scanning electron microscopy and Raman microspectroscopy, the study authors determined that this billion-year-old organism is unambiguously fungus.
In the cell walls, the researchers also found a fibrous substance known as chitin — the oldest evidence of this substance ever found.
"No other Precambrian fossils display such morphology," study author Corentin Loron of the University of Liege in Belgium told VICE. "Thanks to these microfossils, new models can also be calculated and calibrated to refine the age of the origin of Kingdom Fungi and its different members."
Organisms A Billion Years Ago Are Likely More Complex Than Expected
As Loron explained, their findings are important because fungi is part of the umbrella group of organisms known as Eukaryotes, which includes plants and animals.
"This means that if fungi are already present around 900 to 1,000 million years ago, so should animals have been," he said in an AFP report. "This is reshaping our vision of the world because those groups are still present today. Therefore, this distant past, although very different from today, may have been much more 'modern' than we thought."
Of course, it doesn't mean that dinosaurs would have been walking around a billion years ago. According to Loron in an interview with The Guardian, animals at the time would have been very simple, such as a sponge.