Animals may have appeared 200 million years earlier than thought
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Researchers examining microfossils from Mongolia suggest the first animals may have emerged on Earth up to 200 million years earlier than previous scientific estimates.
The team analyzed over 140 microfossils from the Kheseen Biota, a collection of microscopic fossils that could reveal details about early animal evolution. They used scanning electron microscopy to study the samples, discovering new species and structures resembling embryos, some with preserved internal cells.
While the scientists observed well-preserved features typically lost over millions of years, they caution that none of the specimens are definitively identified as animals. The study also incorporated data from the Weng'an Biota in China, a 590-million-year-old deposit known for preserving ancient microscopic organisms.
By comparing the Mongolian and Chinese records and considering estimates from “molecular clocks”, which use genetic differences to estimate when species shared common ancestors, the researchers propose that animal evolution may have begun before the formation of previously used fossil deposits. This research expands knowledge of ancient microscopic life and provides new evidence for investigating the origins of animals on Earth.
