Started out as a fish. How did it end like this?


Tiktaalik was first known to humans in 2004, after skulls and other bones of at least 10 specimens were discovered in ancient stream beds in the Arctic territory of Nunavut. The discoverers, a team of paleontologists including Neil Shubin from the University of Chicago, Ted Daeschler from the Philadelphia Academy of Natural Sciences and Farish Jenkins from Harvard University, described their findings in two Nature papers in 2006.

A local council of elders known as Inuit Qaujimajatuqangit Katimajiit was consulted, and they named Tiktaalik, which translates to a large freshwater fish that lives in the shallows, after him in Inuktitut. The fossils have since been returned to Canada.

Scientists have been looking for a fossil like Tiktaalik, a creature with the tip of limbs, for decades. And where other fossils needed a bit of explanation, Tiktaalik’s obvious anatomy – a fish with (almost) feet – made it the perfect icon of evolution, sitting squarely between water and sea. earth.

Even then, the fossil fish struck a popular nerve, coming on the heels of a Pennsylvania lawsuit case that ruled against teaching creationism as an alternative to evolution in high school biology. For Dr Shubin, society’s collective desire to put Tiktaalik back in the water is a bit of a relief: you would only throw the fish away if you believed in evolution, “which to me is a beautiful thing”, did he declare.

When Ms. Deretsky illustrated Tiktaalik, she depicted it with its behind submerged in water, as the back half of the fossil was a mystery at the time. But in the years since, scientists have amassed more than 20 specimens and seen more of its anatomy, including its pelvis, hind flipper and skull joints.

In particular, CT scans taken by Justin Lemberg, a researcher in Dr. Shubin’s lab, allowed scientists to look inside the rock to see the bones inside. The scans spawned 3D models of the unseen parts of Tiktaalik. Some scans revealed that Tiktaalik had surprisingly massive hips (more like Thicctaalik) and a surprisingly large pelvic fin. The fish, instead of dragging itself with its front flippers alone, like a wheelbarrow, seemed to use its four flippers to move around, like a jeep.

Further analyzes revealed the delicate bones of its pectoral fin. Unlike the symmetrical fin rays of fish, Tiktaalik’s fin bones were noticeably asymmetrical, allowing the joints to bend in one direction. “We think it was because these animals were interacting with the ground,” Dr Stewart said.


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