redOrbit Staff & Wire Reports
Mysterious multicellular fossils believed to be ancient sea creatures may actually be some of the earliest land-dwelling organisms, according to a paper published online on Wednesday in the journal Nature.
The controversial hypothesis has been fiercely criticized, with some paleontologists flatly rejecting the idea, but if true, the finding would push back life’s transition from sea to land by as much as 100 million years or more.
The Ediacaran fossils were first discovered in 1946 in Australia’s Ediacara Hills, and date to 542-635 million years ago. They were long considered fossil jellyfish, worms and sea pens.
Gregory Retallack, an Australian native who has been studying the fossil soils of South Australia, examined the ancient Ediacaran soils with a variety of chemical and microscopic techniques, including an electron microprobe and scanning electron microscope.
The soils with fossils “are distinguished by a surface called ‘old elephant skin,’ which is best preserved under covering sandstone beds,” wrote Retallack, professor of geological sciences and co-director of paleontological collections at the University of Oregon’s Museum of Natural and Cultural History, in his report.
The healed cracks and lumpy appearance of sandy “old elephant skin” are most like the surface of microbial soil crusts in modern deserts.
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