From The Scientist:
Scientists predict that sponges—among the most basic animals—arose a few hundred million years before the occurrence of the oldest confirmed fossil specimens, which date to about 500 million years ago. Now, in a study published today (July 28) in Nature, Elizabeth Turner, a geologist at Laurentian University in Canada, identified structures in 890-million-year-old fossils of organisms similar to modern bath sponges, potentially pushing back the emergence of the animals to at least that long ago.Abby Olena, “890-Million-Year-Old Fossils Are Sponges, Oldest Animals: Study” at The Scientist (July 28, 2021)
The sponges, if confirmed, push the evidence back by 350 million years:
On Wednesday, in a study published in the journal Nature, Turner lays out her case for this hypothesis, suggesting the microstructures discovered in the ancient Little Dal reefs are indeed sponge microfossils, making them almost 350 million years older than the current oldest animal ever described.
It’s a big claim — and one that is sure to be debated — but Fritz Neuweiler, a geologist at Laval University in Quebec who wasn’t affiliated with the study, called the work “a good step forward,” noting the paper is “well-founded, courageous and provoking.”Jackson Ryan, “‘Weird’ fossil from 890 million years ago could be evidence of earliest animal life” at C/Net
The paper is open access.
At the time, we are told, there was only one supercontinent, Rodinia.