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890 million-years-old? Geologist may have discovered oldest animal fossils ever

sponge fossils (James St. John/Flickr)

890 million-years-old? Geologist may have discovered oldest animal fossils ever

A geologist in Canada may have discovered fossils of ancient sponges dating back 890 million years, making the potential discovery 350 million years older than the oldest undisputed sponge fossils.

The fossilized structures found in rock samples potentially show sponges that existed in underwater reefs millions of years ago. The findings may represent the oldest animal fossils ever discovered, Laurentian University professor Elizabeth Turner described in an article published Wednesday in the journal “Nature.”

Scientists have previously estimated that sponges existed before more complicated creatures over 540 million years ago. However, there’s a lack of fossilized sponges discovered by scientists that would prove the timeline for the early creatures.

The fossils discovered by Turner resemble skeletons found in some modern sponges known as keratose demosponges. The skeletons are made up of segments that look like connected branches of a tree.

The geologist told USA TODAY that her discovery is intriguing for scientists and non-scientists alike, who all may learn about the history of how animals — and humans — came to be today.

“We are animals,” Turner said. “And we have a big brain, and we’re capable of wondering about stuff, and we wonder how we came to be.

“What happened before, and what was it like? How did it begin?” she added. “This is really digging into that. I’m shaking up the apple cart.”

If the age of the fossils discovered by Turner is proven true, then the organisms would have lived on Earth before a time when scientists believe there was enough oxygen to support animal life.

The creatures also would have lived prior to widespread ice ages on Earth.

The fossils were found in a remote area of northwestern Canada accessible only by helicopter.

Turner told USA TODAY that some critics may question her findings due to the Earth’s oxygen levels and the conditions that the sponges could have faced.

“Here I am saying, ‘Uh-oh, the first animals appeared before that.’ So they didn’t require that oxygen. So people may be not so comfortable with it,” Turner said.

“This is not the holy grail,” she noted. “It’s just a step toward a better view on animal evolution. “

But the spongelike creatures would have lived in reefs made from bacteria that could have created enough oxygen for the sponges to survive, according to multiple reports.

“We know there has to have been a time, an episode or an interval of hidden evolution in animals prior to 540 million years ago,” Turner said. “The question is — how far back did it go, and what was it like? That’s the big hole.”

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(c) 2021 USA Today

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