Alaska fossil of the bizarre ‘buzz saw’ shark, lost for 29 years, goes on display at the Alaska SeaLife Center
May 21, 2015
Story courtesy of Alaska Dispatch News and Alaska Sealife Center Summer of Sharks Exhibit
In 1986, Richard Glenn, a 23-year-old geology student from Barrow, spotted an odd shape in a foot-long chunk of rock near Atigun Gorge. It consisted of a series of points arranged in a spiral, like the shell of a snail.
“I don’t have much of a background in paleontology,” Glenn told this year’s meeting of the Geological Society of America in Anchorage on May 13. “I’d never seen anything like it. I didn’t know what it was. So I left it there.”
It made sense at the time. Glenn’s project involved mapping the convoluted “jelly roll” of geological formations in the Brooks Range. Fossils were part of the evidence he took under consideration, but they were not very helpful when found out of place. This thing, whatever it was, had dropped from its original location onto a steep scree slope of mixed rock.
The next day his adviser, Gil Mull, arrived from the University of Alaska Fairbanks and, hearing about the fossil, suggested they take another look.
That wasn’t easy, Glenn said. Every bit of rubble on a scree slope looks pretty much like every other bit of rubble. “But we went back and spent the day kicking rocks over.”
They found it and brought it back to camp. Mull didn’t know what it was either. He forwarded the rock to the Smithsonian Institution, where it was identified as the teeth of a Helicoprion, an extinct predatory fish that lived about 280 million years ago.
Glenn noted the name in his master’s thesis, but didn’t see the fossil again. In fact, he couldn’t find out what had happened to it.
Now executive vice president of lands and natural resources at Arctic Slope Regional Corp., he said, “I must have gone to Washington, D.C., 20 times in the last 29 years. When I did, I’d go looking for it, asking around the Smithsonian. But no one knew anything.
“It never came home.”
Ketchikan artist and avid fisherman Ray Troll has made an international reputation with his surreal pictures of fish accompanied with quirky titles like “Spawn till you die” and “Fish hard, die free.” He also has a fascination with paleontology. Museums know who he is. They sell his T-shirts and cups in their gift shops. His success as an artist has helped open doors. He gets tours of the back rooms and is on a first-name basis with scientists and curators.
In 1993 he visited the collection at the Los Angeles County Museum, where he saw a rock with a weird spiral pattern, “sort of being used as a doorstop,” he said. He thought it was a shellfish and wondered why it was with the fish fossils.
“Look again,” his host told him. “Those are shark teeth. That thing’s blown paleontologists’ minds for over 100 years and nobody’s ever figured it out.”
Troll’s mind was similarly blown. What was something that looked like a spring doing in the mouth of a major predator? How did it happen? How did it work?
“Staring into the whorl of teeth, I knew my life was forever changed,” he later recalled.
He became obsessed with the spiral. He featured the animal as the “H” entry in his 2002 “Sharkabet” alphabet book. He contacted every Helicoprion expert he could find.
There weren’t many and they couldn’t tell him much. Nor were there many specimens, only about 150 collected from around the world, and they consisted only of the teeth. Helicoprion’s skeleton was formed from cartilage, not bone. When it died and decayed, the teeth were generally the only part that lasted long enough to be preserved.
From the first discoveries, scientists puzzled over where the teeth went and how they were used. They placed them on the animal’s snout, its tail, its fins. They wondered if they were for defensive purposes, snapping out like a party favor, to use Troll’s analogy.
Chop saw motion
Idaho is the Helicoprion capital of the world, with many fossils found in phosphate mines there. One such whorl found in 1950 had impressions of cartilage from the beast’s head. In recent years a team led by Leif Tapanila put that specimen through a CT scan and teased out clues about where the whorl of teeth fit. In February 2013, they published a paper announcing the results in the scholarly journal Biology Letters.
Several members of the Idaho team made presentations at the Geological Society meeting, which took place in UAA’s ConocoPhillips Integrated Science Building from May 11-13.
Jesse Pruitt, who worked with the CT scan, pointed out one of the key discoveries: The disc of teeth was held in place by a supporting arm of cartilage that projected upward from the bottom jaw. This kept the older teeth on the bottom of the disc from pushing into the jaw tissue when the fish bit down.
The mechanism resembled a circular chop saw, which has given the Helicoprion its popular nickname, the “buzz saw” shark.
Pruitt said the smallest teeth, those toward the center of the spiral, were the animal’s baby teeth. As it grew, new and bigger teeth emerged full size from the direction of the creature’s throat and pushed the older, smaller teeth forward toward the outer lip where they curved downward and formed a coil.
Biologist Jason Ramsay said only 11 of the more than 100 teeth in the whorl were functional. The rest were either emerging, full size or had curled away into the jaw. The circular arrangement resembled the arc of an ulu, but instead of a back-and-forth motion, the circle of teeth cut like an ax. The way the jaws opened forced the food farther back in the mouth. Thus each bite not only further mangled the prey but moved it toward the gullet to be swallowed, probably in large chunks. Helicoprions did not chew their food.
Tapanila said they had tiny teeth on the roofs of their mouths to help hold prey steady as the chomp came down.
But what purpose was served by having teeth grow into one’s throat?
True sharks, related to but not descended from Helicoprion, grow new teeth throughout their lives but shed the old ones. Their teeth, and the teeth of other vertebrates — yours, for instance — each have their own root. But all of Helicoprion’s teeth were attached to a single, continuous root structure. This may have made the whole biting apparatus stronger. But, as each tooth was an integral part of the same base, they could not be shed one by one. So they had to be stored.
(This makes Helicoprion the only animal besides people known to hang onto its baby teeth, though we use little boxes and our reasons are sentimental, not practical.)
The animal needed strong teeth to deliver its lethal bite. Ramsay ran some numbers to show that the jaw of an average size Helicoprion exerted a force equal about half of the that produced by a junk yard auto crusher.
“They could really bite hard,” he observed.
How did a warm-water fish wind up in the Arctic mountains? The Brooks Range is formed of seabeds that have been forced upward over time, Glenn said.
And the world was warmer in Paleozoic times. Paleobotanist Kirk Johnson mentioned that he’d found impressions of palm tree leaves in the Matanuska Valley the day before and said that for 85 percent of Earth’s history the poles have been ice free.
“We’re a pretty cold planet, these days,” he said. “The first primates entered the Americas swinging from tree to tree across Beringia.”
Helicoprion tooth whorls have been found over a wide geographic area. They were clearly a successful species — but an evolutionary dead end. They vanished at the end of the Permian period, about 250 million years ago, in a great “die-off” that sent 90 percent of Earth’s life forms to extinction.
Today all sharks and bony animals have teeth in bilateral pairs, if they have them at all. A rodent’s incisors, carnivore’s canines or herbivore’s molars have matching left and right sides. But Helicoprions and other shark-like fish of their time had all their teeth in a single line.
The tooth whorl provided a biting mechanism that was solid as rock, could grow with the animal and, in evolutionary terms, solved the space problem by tucking away the outgrown teeth.
Physical attributes beneficial to a species, like locomotion and sight, tend to evolve repeatedly in different ways. But nature never tried the buzz saw jaw idea again. “No other living thing has done this,” Tapanila said.
Troll found similarities in the sperm whale, which only has teeth on its narrow bottom jaw and preys on squid similar to what Helicoprion would have hunted. But whale teeth don’t have a single root, and nothing like a wheel of teeth is found among modern animals.
Whatever other unique features Helicoprion had may never be known, “unless we find that holy grail specimen we’re all waiting for,” Tapanila said — a fossil that would show the body, fins and perhaps even organs of the animal.
Troll’s illustrations were used in Tapanila’s Biology Letters report and the companion article in Scientific American that appeared at the same time. They were also a big part of an exhibit at the Idaho Museum of Natural History in Pocatello that opened June 22, 2013, and has since traveled to Tacoma.
The exhibit included key Helicoprion fossils and a mechanical version of the buzz saw bite. Missouri artist Gary Staab provided models of a complete 15-foot fish and the head of a 30-footer made to appear as if it were crashing through the wall. Wall decorations and even the upholstery on a couch were based on Troll’s paintings, many of which were displayed to describe the place of the Helicoprion in paleontological lore.
In 2014, when Troll received the Ocean Ambassador Award from the Alaska SeaLife Center in Seward, he spoke about the shark he’s been obsessed with for more than 20 years, “a shark that has almost driven me mad.”
At his urging, the center — best known for its displays of live fish, seabirds and marine mammals — agreed to host the exhibit starting in April 2015. It’s the first traveling show to come to the center since it opened in 1998.
In February of this year, Richard Glenn was a guest speaker at the center. Someone told him about the upcoming show and asked if he knew what a buzz saw shark was.
“I didn’t, but I did know what a Helicoprion was,” he said. “I told them I’d found one of those fossils in Alaska. And they told me, ‘You need to talk to Ray Troll.’ ”
Glenn was familiar with Troll’s work. He’d noted the Helicoprion in the “Sharkabet” book and said the thought had crossed his mind that he might have an ally in trying to locate his Atigun Gorge specimen.
Troll said he was more than a little skeptical when Glenn called him. “This guy who’s co-captain of a whaling crew in Barrow says he found a buzz saw shark in Alaska? Why hadn’t anyone heard about it? Where was it now? We need to see pictures.”
Mull, Glenn’s thesis adviser, now living in the Lower 48, couldn’t remember where he put the film he shot of the rock in 1986. J. Thomas Dutro Sr, the man who had identified it as a helicoprion had died in 2010. The labyrinthine vaults of the Smithsonian’s National Museum of Natural History contained no easy-to-find records indicating it had ever been received.
Troll started making calls and his buddies in the museum world swung into action. “Ray has more clout at the Smithsonian than I do,” Glenn said.
The museum’s collection manager, David Bohaska, began opening drawers, all of them. “Drawers that didn’t say ‘Alaska’ or ‘fossils’ or anything,” Troll said. After a month of searching, Bohaska found the mislabeled rock from Atigun Gorge.
“I knew it had to be part of the exhibit in Alaska,” Troll said. But would the Smithsonian loan such a rare fossil?
“We weren’t at all sure we’d have it,” said SeaLife Center President Tara Riemer. “But just before the exhibit opened, one morning there it was, in a FedEx box on my doorstep.”
This summer Glenn’s buzz saw shark tooth whorl is on display at the center’s “Summer of Sharks” exhibit. Viewers will see most of the Idaho exhibit with a few tweaks that add information discovered since 2013. There’s an eye-opening video of Troll trying out a metal version of a whorl set on a lever handle. Troll and crew gleefully work it on a variety of things, decapitating fish, chopping carrots, dividing cantaloupe, a tube of toothpaste and a can of Diet Coke.
“It’s a really efficient slicing machine,” Pruitt said.
The speakers list for the Geological Society meeting included Troll, whose book and print titles were cleverly incorporated into a series of academic papers on technical topics like “Caledonide influence on evolutionary ecology in the Alexander Terrane” and “Graptolites of the lower member of the Ninini Fourmation, Roberts Mountains, Eureka County, Nevada.”
Troll talked about his upcoming book of West Coast fossils, written with paleobotanist Johnson, in which he had to go back and insert an illustration of a Helicoprion in Alaska after learning about the Atigun fossil. “Is Richard Glenn here?” Troll asked.
Glenn nodded from his seat in the second row and Troll left the lectern to shake his hand. They had spoken on the phone before, but never met in person.