Scientists found in the Nilpena Ediacara National Park, in Australia, the fossil of a worm that lived 555 million years ago that will help to unravel one of the greatest mysteries of evolution — the origins of the largest animal group on Earth.
Ecdysozoans gave rise to species of insects, crustaceans and nematodes and, even though they existed in abundance, scientists had difficulty finding evidence of their ancestors.
“Ecdysozoans were prevalent in the Cambrian fossil record and we know they didn’t appear out of nowhere. But until now, we didn’t have any concrete fossil evidence to confirm it,” said the lead author of the study published in Current Biology magazine this Monday (16), Ian Hughes, a Ph.D. candidate in the Department of Organismic and Evolutionary Biology at Harvard.
Scientists explained that the discovery of Uncus dzaugisi, made in rocks from the Precambrian period, was in a shape that appeared to have been cemented, with a mold of its ancient ecosystem preserved.
This happened because the layers of sediment that remained on top of the worms were thick materials that compressed the species.
“Imagine pouring concrete over the ocean, waiting half a billion years, and then turning it over to find an entire ecosystem,” Hughes said. “That’s what’s really unique about this location. Because they were all smothered at the same time, we can actually conduct ecological work in Earth’s earliest animal ecosystems.”
The Uncus have similarities with some modern animals — the roundworms — and characteristics that show that they were mobile through space, a novelty for the fossils found from this period.
“Ecdysozoans are so diverse and occupy so many niches, that actually identifying an ancient one and seeing what the ecdysozoans were doing is simply incredible,” commented the researcher.
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This content was originally published in 555-million-year-old worm fossil helps solve mystery of evolution on the CNN Brasil website.
Source: CNN Brasil

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