An artist’s reconstruction of Qikiqtania wakei, in light green, and its larger cousin, Tiktaalik roseae.Credit...Alex Boersma
The New York Times has a story about a newly described fish from the Devonian. Qikiqtania wakei lived about 375 million years ago during the Devonian Period in what is now Nunavut, an Arctic territory of Canada. It was discovered in 2004 by Dr. Neil Shubin. This animal is closely related to a tetrapod-like fish called Tiktaalik roseae, which Shubin detailed in a paper in 2006 and the book "Your Inner Fish" in 2008. Qikiqtaniais interesting because it seems to be an animal that adapted back to swimming.
One of the biggest myths of evolution is that it is a relentless march of progress. In fact, evolution is not a linear track, but a branching tree. New species do not arise as part of some long-term goal; they adapt to new opportunities in their surroundings.
On Wednesday, paleontologists unveiled a fossil that proved a potent antidote for the march-of-progress myth. It was a fish that lived about 375 million years ago, when our ancestors were scaly creatures vaguely resembling giant eels, walking across mud flats with four limbs complete with elbows, knees, wrists and ankles. The newly discovered fossil, called Qikiqtania wakei, belonged to this lineage.
But its anatomy suggests that its ancestors, unlike ours, did not continue the move to land. Instead, they gave up walking to swim again.
“We think of evolution in directional terms,” said Neil Shubin, a paleobiologist at the University of Chicago. “That’s not the case here. You have some species going to land and some actually returning to the water.”
