Fossil find challenges tree of life as we know it

PARIS (AFP) - Organisms long thought to have been the ancestors of early marine creatures may in fact have lived on land, said a fossil study on Wednesday that may prompt an overhaul of the tree of animal life.

If correct, the finding could challenge the commonly held theory that life had thrived in the oceans for hundreds of millions of years before spreading to land.

The fossils, dubbed Ediacaran and dated to 542-635 million years ago, were unearthed in south Australia in 1946, and were long thought to have been the remains of jellyfish, worms and flowery seafloor-dwelling creatures known as sea pens.

Now a geological scientist from the University of Oregon, using state-of-the-art chemical and microscopic analysis techniques, has concluded the fossils more likely belonged to land-dwelling organisms and were not animals at all. They may have been lichen - a composite of a fungus and an algae or bacteria - or colonies of micro-organisms.