Canadian Museum of Nature unveils ancient limbed fish fossil

Fossils of a prehistoric creature that stood as an intermediary point between fish and land animals were unveiled Tuesday morning at the Canadian Museum of Nature, more than a decade after paleontologists made the original groundbreaking discovery in Canada's High Arctic.

Some 60 fossils of Tiktaalik roseae, which lived about 375 million years ago, were returned to Canada this week and will now be housed at the museum, with the permission of the government of Nunavut, after being meticulously prepared and studied for the past decade in the U.S.

The fossils will not immediately be put on public display, but instead will be studied further at the museum. The eventual plan is to return the fossils to Nunavut, although there is no precise timeline yet for when that will happen.

Part of our shared history

Tiktaalik roseae had fins, scales and gills like a fish, but also had a neck that allowed it to move its head independently of its body, like an amphibian.

Inside its fin were bones that would have corresponded to parts of mammalian limbs like the forearm and the wrist, said Neil Shubin, a paleontologist at the University of Chicago who was part of the original discovery team.

Those adaptations mean Tiktaalik roseae would have moved, said Shubin, much like a modern-day crocodile.

"A part of our history is shared with this animal behind me: the history of the origin of our elbows and wrists and necks," said Shubin. "That's what this creature really tells us about -- how did fish evolve to walk on land, and what was our history like when our common ancestor was a fish."

The fossils were originally found by Shubin, Edward Daeschler of the Academy of Natural Sciences in Philadelphia, Farish Jenkins Jr. of Harvard University and their colleagues. 

They found the fossils in the rocks of Ellesmere Island in 2004 after a four-year search in the area, and published their research in the journal Nature in 2006. Their discovery made international headlines.

The "real work," however, began once the fossils were brought south, said Shubin.

"It took years to remove the rock, grain by grain, from the fossils," said Shubin. "That's what you see. You're seeing a lot of hours spent in the lab, turning those rocks into beautiful bones."

An evolutionary 'holy grail'

Fossils of creatures having both fish and land animals features have been found before, but Tiktaalik falls into a gap between 385 million and 365 million years ago, giving researchers more details of the transition.

"That transition from finned to limbed animals has always been one of these sort of holy grails of the evolutionary story," said Daeschler.

"When we're looking at Tiktaalik roseae, we are looking at the common ancestor of all limbed animals on earth."

The name Tiktaalik comes from a word in the Inuktitut language for the burbot, a serpent-like freshwater fish. The name was supplied by Inuit elders in Nunavut.

Along with the Tiktaalik roseae fossils, the Canadian Museum of Nature also debuted about 120 pieces of other lobe-finned fossil fish from the Devonian period, which stretched from 419 million to 358 million years ago.