Researchers have found the planet's oldest fungus in NWT, according to an article published in science journal Nature on May 22.

Found in Tukktut Nogait National Park, the billion-year-old fungus is a surprisingly intricate microfossil, and is now the world's oldest known sample, beating out a 410-million-year-old one found in Scotland. So far there has been no definitive proof of fungi that predates the Cambrian Explosion, which was the sudden appearance of complex animals roughly 541 millions years ago.

One of the authors of the research, Professor Elizabeth Turner, said this marks a "big deal" in how we understand how biological evolution developed.

"Prior to that, we don't have obvious fossils like that, nothing is mineralized prior to 540 million years ago," she said. "The fossil record we think we know is really only the last 10 per cent of our history."

That benchmark of a diverse range of life has to have had a history, she said. "The first 90 per cent (of our history) is a big mystery."

The team found the sample in Tukktut Nogait National Park, known for its vast canyons and rock formations, which the research has revealed to hold additional scientific significance.

Finding a billion-year-old fossil is important, but it being a fungus is "a great big deal," she said, explaining that animals and fungus are closely related.

"Our closest relatives among big divisions of life are actually fungus," she said.

"How do you like them apples?"

The tiny filaments that make up fungus are microscopic and un-mineralized, meaning the chances of observing them are poor. However, the sweep of rocks in Tukktut Nogait National Park happened to carry the clues to their discovery.

The fossils the research team found are only preserved under certain conditions. That means they're only deposited in environments with specific rock types. The researchers identified these promising areas to find places relatively unaffected by geology and tectonics, leading them to the region.

The park had preserved rocks matching the age target for the study. The discovery's fungus was found in a shale, which had to be dissolved to leave the organic matter behind, which Turner called "a tall order. She added that the tiny fossils are deeply fragile.

"Lo an behold we find ... a very diverse assemblage of this type of complex organism, mainly single-celled, but in the case of this fungus, multi-cellular too," Turner said.

"The fact that we find fungus fossils a billion years ago means that fungus and animals had to have diverged before that," she said. "The actual reality of biological evolution of animals has to have gone back prior to a billion years ago because fungus and animals are genetically the closest related organisms ... in the tree of life.

"So that's what the big deal is," she said.

Turner explained this can lead future research to ask how much further back the findings go. To help answer that question, the research team will go to Nunavut, where the rocks are slightly older and may consequently provide more clues to the gap in our planet's biological history.