When a juvenile moon jellyfish loses tentacles, it rapidly reorganizes its remaining limbs to maintain symmetry, a study said.

In the lab, researchers removed the tentacles from the translucent jellyfish. “Each time, they would start reshaping and reorganizing their bodies,” said study author Michael Abrams, a biologist at California Institute of Technology. The process was quick, beginning 12 hours to four days after researchers removed the tentacles. Abrams and his colleagues describe their findings in the Proceedings of the National Academy of Sciences.

The process of realignment, they found, is started by the repeated contraction of muscles that the jellyfish use continually. “Symmetry may be important for the moon jellies to swim and feed successfully, Abrams said.

Fossil may yield soft tissue

A million-year-old dinosaur fossil — and a poorly preserved one, at that — may have yielded traces of intriguing soft tissue. Scientists believe they’ve spotted blood cells and collagen, the protein that makes up connective tissue in animals. Their findings were published in Nature Communications.

Years ago, researcher Mary Schweitzer found what she believed were preserved blood vessels in a T. rex bone, a finding that has since been supported by molecular analysis. But unlike the specimen Schweitzer worked with, the fossils used in the new study by a team at Imperial College were poorly preserved, which suggests that soft-tissue preservation might not be as uncommon as we’d thought.

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