LIVE SCIENCE - The first animals may have appeared on Earth hundreds of millions years earlier than their fossils suggest, a new modeling study suggests.
Previously, the earliest fossil evidence of animals dated to around 574 million years ago, during the Ediacaran period (635 million to 538 million years ago). In the new paper, a research team argues that we can't just rely on the spotty fossil record, and suggests that animals first appeared up to 200 million years earlier than the oldest known animal fossils.
In the study, published Friday (Oct. 2) in the journal Science Advances, the researchers argue that the absence of animal fossils in some exceptionally well-preserved ancient rocks doesn't mean the animals were absent from history. Instead, they suggest that the fossil record may be missing a key chapter of animal evolution, potentially pushing the origins of animals back to between 800 million and 700 million years ago.
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"So the game is basically how much does it predate our first fossil discovery by and what happened in that evolutionary black box between when they actually originated versus when we get our first fossil window," Karma Nanglu, an assistant professor of evolutionary paleobiology at the University of California, Riverside, who wasn't involved with the study, told Live Science.