“It could just be some microbial wiggles,” said Jonathan Antcliffe, an evolutionary biologist specializing in sponges at the University of Lausanne in Switzerland. The evidence backing up the claim that they’re remnants of an ancient sponge, he said, “is very, very thin.”The putative fossils were extracted from the 890-million-year-old Little Dal reefs of northwestern Canada, which are now exposed parts of the Mackenzie Mountains. If verified, they would predate the oldest undisputed sponge fossil by about 350 million years — a span of time longer than today and when dinosaurs first evolved. “We’re talking about inserting hundreds of millions of years without a trace” of fossils, said Graham Budd, a paleobiologist at Uppsala University in Sweden who was not involved in the paper. “If we expect the first animals to be tiny and soft,” said Maja Adamska, an evolutionary biologist at the Australian National University who was not involved in the new paper, “this is the best we can expect.”

Source: New York Times July 28, 2021 15:00 UTC