What’s a vintage, empty pack of Marlboro cigarettes doing on exhibit at the Cleveland Museum of Natural History (CMNH)?

“Actually, I have boxes and boxes of cigarette packs that are not yet archived. We are going through them and sorting things out,” says Caitlin Colleary, a vertebrate paleontologist with CMNH. “Cigarette packs were an important fossil collection method in the field in the past. People probably had them on them anyway, so why not use what you have?”

In this case, the cigarette pack—with its flip-top lid, compact size, and availability—made perfect sense to transport small fossils back to the lab.

In fact, a Marlboro pack is part of the exhibit, “Discovering Dunkleosteus terrelli” in the Corning Gallery, a new space for CMNH’s rotating exhibits. The exhibit on the fossil affectionally known as “Dunk” by museum staff and visitors alike is expected to run through summer 2024.

Dunkleosteous Terrelli Fossil“The exhibit tells the museum’s story of finding Dunkleosteus terrelli,” explains Colleary. “We have a long history of locally finding those fossils and probably the largest collection of these fossils in the world. This is a nice way of bringing together a lot of archival materials from the museum’s early years and putting them out there so visitors can see and appreciate them, while telling the discovery story,”

Dunk was a ferocious, armored fish that lived about 360 million years ago. It was an “apex predator,” which means it “ate most anything it wanted to,” according to Colleary.

“Dunkleosteus [fossils] have been found in Poland, Morrocco, and Russia. But we have so many here, it’s unbelievable.” she says. “If you go to any museum in the world where you see a Dunkleosteus’ head, chances are it’s a cast of one of our specimens.”

Dunk did not swim in Lake Erie, however. Before the prehistoric fish became extinct (most likely because of environmental causes, Colleary says), it ruled the shallow, inland ocean that covered Ohio during the end of the Devonian Period—the Age of Fishes.

So, yes, it’s possible that when you are standing in your back yard in Greater Cleveland, you are in a location where Dunkleosteus cruised by, way before any dinosaurs roamed the earth.     

The current Dunk exhibit does not officially originate in CMNH’s new Visitor Hall. But that’s where three models of boney-plated Dunk heads with open mouths and glaring eyes are suspended.

Peter Bungart was hired by the Cleveland Museum of Natural History as a paleontologist in 1923They appear to “swim,” making some younger visitors decide not to get too close. The museum owns four skulls that are authentic fossil material, but Dunk’s body was cartilaginous (like a shark’s) so there are no known fossils other than the heads.

These scary looking models are attached to clever, color-changing, neon tube light body outlines.

Items in “Discovering Dunkleosteus terrelli” include fossils, of course, but there are also a fascinating array of manuscripts, photographs, tools used in the field and in the lab (a hammer, chisel, and knife), notes (some written on three-ring notebook paper like the kind kids in school use), sketches, and correspondence written and owned by of a number of local Dunk hunters. 

Early Dunk fossil discoverers in northeast Ohio included Jay Terrell, a Sheffield Lake hotel owner and avid fossil hunter in the 1800s. Terrell picked his way through the rock layer known as Cleveland Shale, exploring the lakefront and cliffs.

In 1867, Terrell found armored plates of what was later to be identified as Dunkleosteus terrelli (today there are 10 known species of Dunks). Paleontologist David Dunkle, who studied Cleveland Shale fish, is also given credit for part of the big fish’s scientific name.   

Peter Bungart was only eight years old when he would follow Terrell on his Dunk digs, according to the North Ridgeville Historical Society. Bungart, who died in 1949, went on to become a CMNH paleontologist, continuing his search for Dunk fossils in the black shale.

“Bungart is one of the fascinating people featured in the museum’s exhibit,” says Colleary, who joined CMNH in 2020 after working with the Smithsonian Institution. “There are all kinds of stories about him, including one where he tied himself to a tree and lowered himself down the side of a cliff to look for fossils. It’s amazing what connections this museum has to the history of Dunkleosteus terrelli.”

Many CMNH Dunk fossils were found between 1965 and 1967 when Interstate 71 was being constructed along the valley of Big Creek in Cuyahoga County.

Dunk, the giant armored fish Dunkleosteus terrelli“Those big infrastructure projects sometimes reveal fossils,” says Colleary, who partly focuses on molecular taphonomy and the origin of fossils in her work. “They were bulldozing through so much rock there and whole groups from this museum were just following behind picking up pieces of rock to bring back here.”

Dunk was named Ohio’s official State Fossil Fish in 2021, primarily because of the state’s incredible fossil finds. But it also deserves recognition because Dunk is just one amazing creature, says Colleary. For one thing, Dunk didn’t have teeth.

“He lived in the early evolutionary days of jaw development,” she explains. “He sharpened his jaw bone by opening and closing his mouth. He would sharpen the jaw bones each time, kind of making his own teeth. It was sort of like sharpening scissors.”

But that wasn’t the only unique feature. “Dunk was a strange creature,” Colleary says. “You know how when we open our mouths our lower jaw goes down? Dunk also had a hinge on the top of his head that also allowed him to open up really, really wide.”        

However, Dunk does have one mystery swirling about him: Just how long was he?

It was originally thought that Dunk grew to be up to 30 feet long, but recent research suggests that he may not have been as long as we thought—topping out at 11 feet to 13 feet.

Even if scientists have yet to agree on Dunk’s size, we know he wasn’t intimidated by the sharks that patrolled the same waters. Colleary says she believes sharks probably benefited and thrived after the demise of Dunk.    

Dunkleosteus terrelli jawbone“One of the frustrating things about science is that just because we have new research doesn’t mean it is a fact,” she cautions. “But I am really excited about new research methods that are being done on Dunk’s body size. Scientists have been trying to figure out how big Dunk was for 100 years. Estimates cite his length to be 33 feet max, but also all the way down to 10 feet.”

Colleary adds that it is difficult to estimate certain details on animals that became extinct millions of years ago—especially when there is nothing like them around today.

“Paleontologists often look at modern animals to better understand animals from the past and we don’t have that with Dunk,” she explains. “It’s a cool mystery and one we hope to solve with more discoveries.”

Colleary compares the chance of finding a new Dunk fossil to finding “a specific dead fish in the ocean.” It’s really tough, but she says she’s convinced there are more out there, and some may be even hiding in Ohio.

In the meantime, CMNH is now safely archiving what Dunk specimens it already owns.

As part of the museum’s $150 million, 10-year expansion and renovation transformation project (with help from  a grant from the National Science Foundation), all collections will be re-housed in environments that protect against deterioration.

That protection includes Dunk fossils that could fall to pyrite disease (a chemical reaction caused by exposure to humid air), which would turn them into powder.

“I encourage everyone to come to the museum to visit our Dunkleosteus terrelli in the new exhibit,” says Colleary. “I know he has been a favorite here at the museum for a long time.”