(p. A3) In a trove of fossils dug up decades ago in Wisconsin, a team of paleontologists say they have discovered the oldest known prehistoric scorpion species—and clues about how early organisms evolved to venture onto land.
The arachnids, which were well-enough preserved that researchers could study their internal anatomy, wandered the rich shallow waters of its ancient habitat. Yet the species had cardiovascular and respiratory systems like modern scorpions that could breathe air, say researchers who described their findings in a paper published Thursday in Nature Scientific Reports.
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The researchers dated the fossils to the Silurian Age, a period in the Paleozoic Era between 443 million and 416 million years ago when shallow waters and abundant sunlight allowed colorful reefs and other ancient life to make their debut.
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Joanna Wolfe, who works in the organismic and evolutionary biology department at Harvard University, said the Wisconsin quarry is famously home to marine fossils, so they are “definitely not fully terrestrial, but they are older than the oldest truly terrestrial body fossil of a millipede-like [organism] 427 million years ago.”
“It’s plausible to me that indeed there was a more complex pattern of evolution where we’re going from water to land and back to water, and that that could’ve happened more than once,” said Dr. Wolfe, who wasn’t involved in the research.
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(Note: the online version of the story has the date Jan. 16, 2020, and has the title “Ancient Scorpion Offers Clues to How Animals Moved From Sea to Land.”)