Reconstruction by: Alex Boersma

Neil Shubin, PhD, the Robert R. Bensley Distinguished Service Professor of Organismal Biology and Anatomy at the University of Chicago, discovered both the Qikiqtania and Tiktaalik fossils days apart in 2004, at a site on southern Ellesmere Island, Nunavut, in Northern Arctic Canada. The name Qikiatania comes from the Inuktitut word Qikiqtaaluk or Qikiqtani, the traditional name for the region where the fossil site occurs. The species designation wakei is in memory of the late David Wake, an eminent evolutionary biologist from the University of California at Berkeley.

Tom Stewart, PhD, and Justin Lemberg, PhD, who were then postdoctoral scholars at UChicago, CT scanned a rock containing the fossil pectoral fin and discovered its distinctive shape. The team’s analysis of where it sits on the tree of life places it, like Tiktaalik, adjacent to the earliest creatures known to have finger and toes. Even though Qikiqtania’s distinct pectoral fin was more suited for swimming, its curved paddle shape was a distinct adaptation, different from the jointed, muscular legs or fan-shaped fins we see in tetrapods and fish today.

“Tiktaalik is often treated as a transitional animal because it’s easy to see the stepwise pattern of changes from life in the water to life on land. But we know that in evolution things aren’t always so simple,” said Stewart, who is now an Assitant Professor at Penn State University. “We don’t often get glimpses into this part of vertebrate history. Now we’re starting to uncover that diversity and to get a sense of the ecology and unique adaptations of these animals. It’s more than simple transformation with just a limited number of species.”

Sixteen years later, the discovery of Qikiqtania became another pandemic story. Postdoctoral researchers Justin Lemberg, PhD, and Tom Stewart, PhD, CT scanned one of the larger rocks in March 2020 and realized that it contained a pectoral fin. Unfortunately, the rock was too large to get a high-resolution image, and they couldn’t do much more with it once the pandemic forced labs to close.

In the summer of 2020 when campus facilities reopened, they contacted Mark Webster, PhD, Associate Professor of Geophysical Sciences, who had access to a saw that could trim pieces off the specimen so that a CT scanner could get closer and produce a better image. Lemberg and Stewart carefully marked the boundaries on the block and arranged an exchange outside their lab in Culver Hall. The resulting images revealed a nearly complete pectoral fin, including the distinctive humerus bone.

“That’s what blew our minds,” Shubin said. “This was by no means a fascinating block at first, but we realized during the COVID lockdown when we couldn’t get in the lab that the original scan wasn’t good enough and we needed to trim the block. And when we did, look at what happened. It gave us something exciting to work on during the pandemic. It’s a fabulous story.”

This research was supported by the Brinson Foundation, the Academy of Natural Sciences of Drexel University, the University of Chicago Biological Sciences Division, the Polar Continental Shelf Project of Environment Canada, the Nunavut Department of Culture and Heritage, the Hamlet and Hunter and Trappers of Grise Fiord, and the National Science Foundation.