[ti:Study Confirms Unusual Fossils Came from an Animal]
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[00:00.00]Scientists say they have confirmed that strange-looking fossils
[00:07.23]from more than 500 million years ago are remains of an animal.
[00:14.75]That would make it one of the earliest known creatures.
[00:20.53]The fossils are found within rocks.
[00:25.26]They are round with many lines,
[00:27.92]and look similar to the markings of a leaf.
[00:32.31]The fossils were first described in 1947.
[00:39.47]They have been found in Australia and Russia.
[00:43.57]Some are very small; others are over a meter long.
[00:49.21]Scientists have named the mysterious ancient organism
[00:54.90]that left these fossils behind "Dickinsonia."
[01:00.21]But what exactly was it?
[01:03.32]In the past, some scientists suggested it was an animal.
[01:09.38]Others believed it was a single-celled organism called a protist.
[01:16.69]Researchers presented evidence that Dickinsonia
[01:22.07]was an animal in a recent paper.
[01:25.49]The paper appeared in the publication Science.
[01:30.33]The most important evidence was that Dickinsonia fossils found in Russia
[01:39.68]contained carbon-bearing substances produced by animals.
[01:45.43]Experts not connected to the study called that evidence strong.
[01:52.82]They also said most scientists who had studied the fossils
[01:58.62]already believed that Dickinsonia was probably an animal.
[02:04.89]Douglas Erwin is with the Smithsonian Institution.
[02:10.63]He said he is sure the fossils are from an animal.
[02:16.04]It is not clear when Dickinsonia lived.
[02:21.24]Some fossils are about 558 million years old,
[02:27.04]said Jochen Brocks of the Australian National University in Canberra.
[02:34.17]He was one of the researchers involved in the study.
[02:39.73]Brocks considers Dickinsonia to be "the very oldest animal
[02:46.13]that we can be sure about.
[02:48.09]He added that it is about 2 million years older
[02:52.53]than another widely accepted animal fossil.
[02:57.44]Brocks said scientists do not know much about what Dickinsonia looked like.
[03:05.18]But he said they do know it was "soft and flexible."
[03:10.40]Dickinsonia was not the first animal on Earth.
[03:15.99]Analysis of the genetic materials of living animals suggests
[03:21.82]that animals first appeared more than 720 million years ago.
[03:28.35]But scientists have never found fossils that old.
[03:34.25]I'm Susan Shand.
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