It was a lumbering, wide-headed creature with tiny, close-set eyes, and it likely had to wait on a stream bottom for its prey to swim within reach. But when that happened, watch out! One powerful chomp, with fangs up to 1 1/2 inches long ... .
Rest assured that this scenario comes from the distant past -- 375 million years ago, more or less -- but a team of scientists from Philadelphia, Harvard and Chicago breathed new life into it earlier this month.
They announced the discovery of this 6-foot-long prehistoric predator found in a harsh rockscape 700 miles north of the Arctic Circle. Dubbed Laccognathus embryi, it was among various kinds of fish that had developed bony, muscular "lobed" fins -- the precursors of limbs.
The team included paleontologists Jason P. Downs and Ted Daeschler from the Academy of Natural Sciences in Philadelphia, along with Harvard University's Farish A. Jenkins Jr. and the University of Chicago's Neil Shubin, who have been studying these kinds of creatures for years.
Mr. Daeschler, Mr. Jenkins and Mr. Shubin are best known for their 2006 discovery of another ancient fish, Tiktaalik roseae, which had a very unfishlike neck and limb-like fins that may have allowed it to creep onto land for brief periods.
Laccognathus, the "new" fish, is a more primitive beast, though it lived at the same time. It is a distant cousin of humans, not a direct ancestor. Yet already it is helping to provide a richer picture of a time when Europe and North America were fused together.
Previously, close cousins of this fish had been found in Latvia and Russia, so the new find provides further confirmation that there was once a "Euramerican" landmass, said Richard Cloutier, a biology professor at the University of Quebec at Rimouski.
"Ted and his team have been doing a fantastic job," said Mr. Cloutier, who was not involved with the research.
Over the course of five field trips from 2000 to 2008, the authors of the new paper, published online in the Journal of Vertebrate Paleontology, found parts of at least 22 Laccognathus specimens.
The fossils have a burnt reddish color, not unlike the red brick of the building where they are housed, the Academy of Natural Sciences. The best specimen is a nearly complete skull, found in 2004, which enabled the team to see how many of their previously discovered fragments fit together.
"It's kind of like finding a Rosetta stone," Mr. Daeschler said. "That becomes the proof that all these things belong to one species."