By Devin Powell
Worms may have first burrowed into mud more than 550 million years ago. The tunnels they apparently created, preserved in fossilized sediments and reported in a new study, could be the oldest example of animals significantly churning up the ground.
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That newly plowed seafloor in turn might have helped to spur the rise of new kinds of macroscopic life late in the Ediacaran period — just before the Cambrian explosion produced most of the major animal groups around today.
“We think that Ediacaran organisms diversified as a reaction to habitat remodeling by … burrowing,” says Dima Grazhdankin, a paleontologist at the A.A. Trofimuk Institute of Petroleum Geology and Geophysics in Novosibirsk, Russia, and coauthor of a new paper published online March 19 in Geology.