Margaret Munro, Canwest News Service
May 26, 2010
A "treasure chest" of fossils on a windswept B.C. mountaintop is back in the headlines, thanks to an intriguing little creature that zipped around the ancient seas using jet propulsion.
The carnivore — fossilized in the Burgess Shale half a billion years ago and now identified by a Toronto team — is one of the oldest and most primitive relatives of modern squids, octopuses and cuttlefish.
The discovery has propelled the ancient creature, named Nectocaris pteryx, onto the pages of the Thursday's edition of the British journal Nature, where it is pictured alongside NASA's space shuttle that's taken jet propulsion to much greater heights.
Evolution has just begun to play with that concept when Nectocaris pteryx prowled the oceans 500 million years ago. It later was perfected in squids, cuttlefish and octopuses — which are unique among animals in the way they can shoot through water using "built-in hydro jets that can even send them squirting through the air like little rockets on a tail of water," the journal says.
The journal says the creature had a nozzle-like funnel on its snout that was able to "swivel like a pivoted cannon," and expel water in any direction.
"It's was a very clever way to get around," says paleontologist Jean-Bernard Caron, of the Royal Ontario Museum, noting that the fossilized animal has long been a mystery.
The first specimen was picked up decades ago in the famed fossil beds of the Burgess Shale, now a world heritage site atop a mountain in Yoho National Park, along the B.C.-Alberta border.
The specimen was hauled back to Toronto, but no one was quite sure where the creature fit on the evolutionary tree because of the fossil's squashed appearance and "ambiguous" characteristics.
It could have been a relative of anything from a lobster to a fish, says Caron.
Caron suggested University of Toronto PhD student Martin Smith take another look at both the original fossil and 91 other specimens that have been collected on the mountaintop in the last three decades.
"It turned out to be more interesting that I thought initially," says Caron, noting that the discovery has pushed back the origin of jet-propelling animals, known as cephalopods, by at least 30 million years.
What has emerged is a clear — and rather cute — picture of Nectocaris pteryx, which measured up to five centimetres long in the fossils.
The kite-shaped little predator had eyes perched on stalks — "It could probably see in all directions," says Caron — and two long, grasping tentacles, which were likely used to catch and consume prey. It swam with large lateral fins and "probably used its nozzle-like funnel to accelerate by jet propulsion," the journal reports.
It also had gills that the scientists say appear in some fossils to be choked with mud, suggesting that the animals were killed in an underwater mudflow, says Caron.
The Burgess Shale, discovered a century ago, is a paleontologist's dream — a "treasure chest," as Stephan Bengston, of the Swedish Museum of Natural History, writes in Nature.
Field crews — who continue to explore the area for new fossils and fossil beds — have uncovered tens of thousands of ancient organisms belonging to about 200 species in the Burgess Shale, from a time when the first complex animals on Earth emerged about half a billion years ago.
The planet has been reshaped considerably since then, with the fossils and remains of ancient tropical seas getting pushed by geological forces on to mountaintops in the Canadian Rockies.
http://www.vancouversun.com/technology/Mystery+fossil+early+squid+family+ancestor/3074055/story.html
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