- Canadian fossil hunters have made a rare find of exquisitely
preserved marine animals in Newfoundland, remnants of the first complex
organisms to evolve on Earth and unlike anything alive today.
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- The fossils look like delicate miniature ferns, although
the researchers believe they were animals and not plants.
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- They would have lived deep on the ocean floor, out of
reach of the sun's rays, about 575 million years ago.
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- That was the start of a period of dramatic evolutionary
change on the planet, when, after four billion years of microbial life,
more complex organisms began to appear, says Guy Narbonne, a researcher
at Queen's University in Kingston.
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- Fossils from the earliest days of the Ediacaran Period
have been found only on Newfoundland's Avalon Peninsula, where this discovery
was also made.
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- Hundreds of thousands have turned up on the peninsula,
among them the oldest known specimens of their kind.
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- This latest discovery, made two summers ago but announced
this week in the prominent journal Science, is exciting for researchers
because, unlike previous finds, these fossils are three-dimensional, not
flattened imprints in the rock.
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- They can provide a better idea about how these most ancient
of complex organisms lived.
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- "Is this real?" Dr. Narbonne asked himself
after Allison Daley, a field assistant to one of his graduate students,
noticed the fossils while exploring a dark-coloured outcrop in Spaniard's
Bay, which he says is about a 90-minute drive from St. John's.
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- He instantly knew the find was significant.
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- "It didn't take me long to realize that this was
unlike anything that had ever been seen before," Dr. Narbonne says.
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- Although the fossils look like plants, he says there
is evidence they were animals that fed on suspended material in the ocean,
in the way that coral does today.
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- They are preserved so well because they were caught in
an underwater current of fine mud that may have been generated by an earthquake
or a giant storm.
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- Of the hundred fossils found in the outcrop, the largest
is 12 centimetres long.
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- Two-dimensional specimens found in Portugal Cove South,
also on the Avalon Peninsula, measure as long as two metres.
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- The longer ones are made of small, similar units.
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- The Spaniard's Bay find is not as rich as the famous
Burgess Shale in the Rockies, but it is similar in that it represents a
time in Earth's history when life was changing rapidly.
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- The marine-life fossils in the Burgess Shale are about
520 million years old, from shortly after what is known as the Cambrian
Explosion.
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- During this time period, many major animal groups familiar
to us appeared during what in evolutionary terms is a blink of an eye.
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- The Newfoundland fossils are from a mysterious period
considered the "fuse'" of the Cambrian explosion, in which the
ancestors of mollusks, sponges and other marine life began to evolve.
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- Scientists have had trouble finding fossils because they
were soft-bodied and didn't have skeletons or shells that leave an easy-to-detect
record in rock.
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- But the deep-water fernlike creatures in Newfoundland
are unlike any species alive today.
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- They evolved early, but didn't survive.
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- Dr. Narbonne says: "They were a failed experiment."
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