Scientists say a startling finding in a neglected rock sample “blew our minds”
A little alligator-like creature abandoned the lure of adventure and a new living on land some 375 million years ago in favor of its familiar aquatic habitat.
Scientists have described Qikiqtania wakei, a newly discovered species of fishapod after its fossil remained in storage for years while other, more spectacular “missing links” were explored.
The species exhibits traits of both fish and tetrapods – animals with the four-limbed body plan shared by all vertebrates on land.
According to a new study, its short legs were more adapted for swimming than walking.
The specimen precedes the well-known Tiktaalik roseae, which is regarded as a probable progenitor of terrestrial animals.
Qikiqtania was modest compared to Tiktaalik, which could reach heights of 9 feet. Both were discovered in the Arctic of Canada.
Qikiqtania was identified based on fragments of its upper and lower jaws, neck, and scales.
Importantly, a complete pectoral fin with a recognizable humerus limb bone lacks the ridges that would reveal the location of walking muscles and joints.
Instead, the upper arm of Qikiqtania was smooth and curved, better adapted for life underwater.
Its distinctiveness indicates that it returned to paddling after its ancestors began using their limbs for walking.
Professor Neil Shubin of the University of Chicago, the study’s lead author, stated, “At first, we thought it was a juvenile Tiktaalik because of its small size and maybe immature processes.
“However, the humerus is smooth and boomerang-shaped, and it lacks the characteristics that would allow it to push up on land. It is unique and indicates something novel.”
On southern Ellesmere Island in the jurisdiction of Nunavut in the Canadian Arctic, he discovered the new species days before discovering Tiktaalik approximately one mile away.
The origin of the name Qikiatania is the Inuktitut word Qikiqtaaluk or Qikiqtani, the traditional name for the region where the fossil site is located.
The specimens were taken from a quarry after seeing a few boulders with unique, white scales on the surface that appeared intriguing.
However, they sat in storage, largely untouched, as the crew concentrated on preparing Tiktaalik.
After nearly 15 years, a CT scan of one of the larger rocks revealed that it contained a pectoral fin.
But it was too deep within to obtain a high-resolution image, and as the epidemic caused labs to close, they were unable to do much more.
Dr. Justin Lemberg, the co-author, stated, “We were attempting to acquire as much CT data of the material as possible before the lockdown, and the very last item we scanned was a huge, unremarkable block with only a few scales visible on the surface.
“When the first hazy photographs of a pectoral fin came into view, we could hardly believe it.
“We knew we could have gotten a better scan of the building if we had more time, but that was on March 13, 2020, and the university ceased all non-essential operations the following week.”
When school facilities reopened in the summer of 2020, they called Professor Mark Webster, who had access to a saw that could cut the specimen into pieces.
The researchers meticulously defined the block’s boundaries and staged an exchange in front of their lab in Culver Hall.
The resultant scans revealed an almost full pectoral fin and upper limb, including the humerus bone.
Prof. Shubin remarked, “This blew our minds. This was not an interesting block at first.
“However, during the Covid lockout, when we were unable to enter the lab, we realized that the first scan was insufficient and that we needed to reduce the block.
“And when we did, consider what transpired. It provided us with a stimulating project to concentrate on during the pandemic. It is a fantastic story.”
Qikiqtania is only marginally older than Tiktaalik. Analysis of its position on the tree of life placed it alongside the earliest known organisms with finger-like digits, alongside Tiktaalik.
However, even though Qikiqtania’s characteristic pectoral fin was better suited for swimming, it was not fully fish-like.
Its curving paddle shape was a remarkable adaption, distinguishing it from the modern tetrapods and fish with their muscled, jointed legs and fan-shaped fins.
There is a propensity to believe that creatures evolved in a straight line that connects their prehistoric forms to modern-day organisms, however, Qikiqtania demonstrates that some animals took an alternative path that ultimately failed.
Dr. Tom Stewart, the co-author, stated, “Tiktaalik is commonly regarded as a transitional animal since it is simple to observe the gradual pattern of changes from aquatic to terrestrial life.
“However, we know that evolution is not always so straightforward. This portion of vertebrate evolution is rarely uncovered.
“Now we’re beginning to understand the ecology and special adaptations of these species, as well as their diversity. It involves more than the simple change of a few species.”
