for National Geographic News
"Daisy chains" of small fossil creatures recently discovered in southwest China reveal an extremely ancient and bizarre type of animal grouping, scientists say.
The shrimplike marine organisms, a previously unknown species that lived around 525 million years ago, were found linked head-to-tail at the fossil-rich Chengjiang site in Yunnan Province.
The fossils show 22 complete or partial chains containing up to 20 animals, a team led by Xianguang Hou of China's Yunnan University reports in this week's issue of the journal Science.
The fossil sample contained just one unattached individual, which was the longest specimen found at just under an inch (2.4 centimeters).
"It's a really fascinating finding—quite extraordinary, and a big puzzle," commented Nicholas Strausfeld, a regents' professor at the University of Arizona.
"The regularity of this row of animals is amazing," added Strausfeld, who wasn't part of the study team.
The extinct species, which is due to be named shortly, was a crustacean ancestor with a head shield—or carapace—and a segmented body, said team member Derek Siveter, professor of earth sciences at the University of Oxford in the U.K.
"If you found one on your plate at the local restaurant, you'd identify it as a shrimplike thing," Siveter said.
The interlinked fossil chains remained intact despite becoming stretched and twisted on the seabed.
"You can see quite clearly where individual animals have been bent at right angles, but the integrity of the chain is maintained," Siveter said.
While it's possible the animals lived on the seabed, the study team thinks they swam or floated in the water column.
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