A cautious news article published in the magazine titled “Potential Evidence of the Earliest Animal Life” stated, “If confirmed, these findings may represent the earliest known animal fossils and may be more than the next oldest undisputed sponge. Fossils are about 350 million years old.”

This will also make them more than 300 million years older than the oldest animal fossils confirmed so far. 574 million-year-old fossil from Mistaken Point in the Netherlands and Dickinsonia, an oval, leaf-shaped sea creature that grows to 1.22 meters long and lived 558 million years ago.

The oldest sponge before-widely regarded as the earliest animal group-lived 535 million years ago.

Turner said that when she was studying microorganisms themselves for her PhD in the 1990s, she first discovered these fossils in the pockets and crevices of ancient coral reefs called stromatolites, which were constructed by photosynthetic microorganisms called cyanobacteria. .

Although ancient coral reefs are now located in the Arctic — more specifically, their fossil remains are limestone deposits from the Mackenzie Mountains in the northwestern region near the Yukon border — they were closer to the equator 890 million years ago. Located in the middle of the supercontinent named Rodinia in the shallow inland sea.

These fossils, like worms, are only half the width of a human hair, branching and then reconnecting. Turner is very interested because they are complex structures and she suspects that they are not made of microorganisms. She has been puzzled by them for decades, returning regularly to collect more samples.

And recently, Joachim Reitner in Germany, Robert Riding of the United States and Jeong-Hyun Lee of South Korea, Published research shows how to form similar fossils from keratinous sponges, the type of sponge used to make commercial bath sponges.

“They are exactly the same as what I had in older rocks,” Turner said. “There is no other really feasible explanation for the material.”

She said that the reef pockets and cracks in the Mackenzie Mountains where the worm-like sponge fossils were found are similar to the environment in which sponges live today.

They are too dark for the cyanobacteria to survive on their own, so microorganisms will not compete with sponges for space and other resources. But the distance was close enough that the sponge could capture some of the oxygen produced by microorganisms, which was in short supply at the time.

These microorganisms may also produce food sources in the form of mucus—their modern relatives still do so, giving them the nickname, “pond scum.”

What do other scientists think

Since peer review is usually anonymous, it is unusual that Nature revealed that Reitner, Riding, and Lee had peer reviewed Turner’s articles. Both Riding and Lee confirmed that they believed Turner’s explanation was correct.

Riding said this was a “very interesting discovery.”

“I think the order and cleanliness of this pattern is very unique,” he told CBC News in a telephone interview, noting that the fossils are exceptionally well preserved. “If I found this pattern in a young rock, I would say with certainty that it is a sponge.”

He said that sponges have long been considered the earliest animals and are expected to evolve around the time these fossils were formed.

In other words, Riding admits that the simplicity of fossils and their extraordinary age means that some other scientists may need to be more convincing.

He believes that more people will start looking for these types of fossils and may start to check them for biochemical fingerprints left by sponges, which have been found in younger fossils. He said it would convince doubters, but added that “in my opinion, it is a fossil sponge.”

Some researchers are skeptical

Other researchers contacted by CBC News were skeptical.

Jonathan Antcliffe is a paleontologist at the University of Lausanne in Switzerland. Previously controversial other “oldest sponge” fossil discoveries.

He said that fossils are usually identified by the unique and unique characteristics of the group. There are many sponges, including hard bone elements called spicules, which can be well fossilized. These are not found in this fossil.

Although horny sponges do not have needles, Antcliffe says they are one of the “strangest” groups of modern sponges. He added that needles should exist in even the earliest sponges, because they exist in a microbe that is thought to be the ancestor of the sponge.

Unlike Turner and Riding, he believes that these fossils may be made by many different kinds of microorganisms. “These things can absolutely be anything,” he told CBC News. “There is nothing special here at all.”

Qing Tang I have written before about the lack of truly ancient sponge fossils This is a “problem that bothers paleontologists” because they are thought to have evolved earlier than the oldest fossils, and most modern sponges (but not horny sponges) have hard bones and should be easily fossilized.

Some of his research found that some very old sponges may not have those hard skeletons.

But he said that in this case, these fossils reminded him of another fossil from 635 million to 538 million years ago, which was originally thought to be a sponge. After a more detailed 3D analysis, Researchers believe these fossils are more likely to be made by microorganisms.

He suggested that more sophisticated 3D analysis is needed to confirm Turner’s findings.

“This finding is very interesting overall,” Qing said in an email.

“If the explanation of the keratinized sponge is finally confirmed, especially considering its age, it will be a big step towards a better understanding of early animal evolution… However, as the title suggests, these structures are best due to relatively few It is called possible sponge fossil character retention.”