This week on Wednesday, Canadian scientist Elizabeth Turner claimed that she has found evidence of sponge fossils which are about 890 million-year-old and could be the sign of oldest animal life on Earth. These sponge fossils are discovered in the remote mountain area of northwest Canada. According to Tuner, this new finding could change the scientist’s belief about the way animals evolve, reports The Guardian.
When the rock samples from the Mackenzie Mountains are examined under a microscope, a tubular 3D structure made of calcite was observed. The material nature is the same as the younger bodies of fossils of sponges. Tubules are about the width of human hair branching out and reconnecting to form a 3D structure. These features were formed about 890 million years ago by bacteria.
“At first, when you look at those features, you realize that they look like a bunch of wiggles. But as you try to follow each strand, you realize that even in thin sections they form a complex 3-D mesh network,” said Prof Elizabeth Tuner, at Laurentian University in Sudbury, Ontario.
Also, she said that as the result of the wonderful work of others, earlier examples of the same microstructures were found in the fossils of sponge bodies so that these structures are compared with skeletons of a variety of keratose or corneal sponges.
How are sponges skeletal formed?
In the journal Nature, Turner described how these fossils are formed. She said these sponges are assumed to be mineralized from a few millimeters to more than a centimeters. To form the sponge’s skeleton the soft tissue is supposed to fossilize first and then form the 3D network of collagen-like fibers. As time passes, these skeletal fibers decompose, leaving hollow tubules that are then filled up with calcite crystals.
What do earlier studies on sponges say?
Previous studies by scientists say that sponges emerged in the early “Neoproterozoic era” which is between 800m and 540m years ago. Scientists believe that during this period the rise in the oxygen level provides a space for animal life. And before this event, the oxygen levels were too low for animals to flourish.
But if this new report on sponge fossils comes true then this contradicts the scientists’ research. As the sponges would have existed 90million years before the Neoproterozoic event.
“If I am not mistaken when I interpret the material then earlier animals did not have the same oxygen requirement as those we have assumed to date. We may have had early sponges a while ago, living in a relatively low oxygen world and the complex animals had to wait for some time,” she added.
What do other scientists say?
“I think she is on solid ground. I think it’s well worth publishing. It makes evidence to others for consideration,” said David Bottjer, a paleobiologist at the University of Southern California.
Joachim Reitnern, a geobiologist at Gottingen University in Germany said, “I think these are old sponges – only this type of organism has this kind of organic filament network.”
A sponge expert at Sweden’s Uppsala University, Paco Cardenas said, “The moment was amazing. Having discovered sponge fossils from nearly 900 million years ago will significantly enhance our understanding of the early evolution of animals and could change our outlook on evolution.”