On the News @ The Washington Post
Time is running out to determine if China holds the world’s oldest animal fossils
“The rocks of the Doushantuo Formation, in China’s Guizhou Province, are sprinkled with tiny, ancient fossils. They are no more than a millimeter in length. The 600-million-year-old organisms are preserved with such detail that the fossils, when freed from the rock in a chemical bath and scanned with X-rays, reveal not only individual cells but possible cell nuclei. Some fossils are jagged and round, like wizened Koosh balls. Other orbs, among the most intriguing specimens, are split by Y-shaped seams.
When viewed from the side, the cellular clusters look a bit like pie sliced in thirds. When viewed by biologists, the clusters also look a bit like animal embryos, frozen in time.
“If they are animals, they’d be the oldest animals in the fossil records,” said John Cunningham, a paleobiologist at the University of Bristol in Britain. Cunningham is not convinced that the organisms, known as the Weng’an biota, are indeed ancient animals. In a report published Wednesday in the Journal of the Geological Society, Cunningham and his co-authors examined the best evidence for and against the case that the fossils are from animals. Their answer is: They don’t know.
Ancient trilobites and other scattered specimens provide convincing evidence that animals lived 530 million years ago. Given what scientists know about the rate at which organisms branch off from common ancestors, the first animals should appear in the fossil record about 70 million years or so before those creatures — right around the time of the Weng’an biota.” (…) READ MORE
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