for National Geographic News
Soft tissue recently found in 68-million-year-old Tyrannosaurs rex bones is actually modern-era bacterial slime, scientists say, challenging what some call one of the most remarkable paleontology findings of the 21st century.
In 2005 soft, pliable tissues were found inside Tyrannosaurs rex bones—the first evidence that dinosaur tissue had survived throughout time.
A new team now says such "soft tissue" is actually slime that coated the inside of the bones and filled in spaces once occupied by blood vessels and cells.
"[It's] the same stuff you feel in a bucket of rainwater that you leave sitting in your backyard for a week," said study lead author Thomas Kaye, a paleontologist at the University of Washington in Seattle.
But authors of the 2005 study, published in the journal Science, stand by their claims.
The new research appears today in the journal PloS ONE.
Kaye and his team examined bones of more than 15 specimens that ranged from dinosaurs to ancient sea monsters to mastodons, and found that they all shared tissue-like structures.
But upon closer inspection with an electron microscope, the researchers say the structures became something less enticing: bacterial slime.
According to Kaye, bacteria seep into the bones with water and excrete slime that coats surfaces and fills in spaces, such as those left by blood vessels.
"Eventually this biofilm mineralizes," he said, likening the slime to plaque hardened to teeth.
When Kaye and colleagues examined the various bones with an electron microscope, they noticed microscopic spheres similar to those seen by Mary Higby Schweitzer, the North Carolina State University scientist who led the 2005 study.
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