For nearly 40 years, the Weld County Triceratops 鈥� affectionately known as 鈥淧ops鈥� 鈥� has been stuck in an awkward spot for a fossil of its stature. A dinosaur for the people, Pops has been a very public figure, on display behind glass in various county buildings. Yet the most complete horned dinosaur skull ever found in Colorado had never been thoroughly examined by paleontologists 鈥� it was essentially lost to science.
Thanks to a new agreement between Weld County leadership and researchers at the Denver Museum of Nature and Science, that has now changed.
On a recent afternoon in the museum鈥檚 fossil lab, dinosaur preparator Salvador Bastien bent over the skull of Pops with an air scribe 鈥� a tool that works like a tiny, air-powered jackhammer.
鈥淲e're using this to remove the plaster cleanly from the fossil so that we can see all of the actual bone and study the true shape of what this animal would look like in life,鈥� he explained.
The air scribe is slowly revealing bone that adds a new twist to the story of the Weld County Triceratops: the creature is likely not a Triceratops at all.
A big find
Paleontology has come a long way since February of 1982, when Kenneth Carpenter and Emmet Evanoff 鈥� both grad students at the time at the University of Colorado Boulder 鈥� first stumbled on the fossil that would come to be known as Pops.
Hundreds of millions of years ago, 鈥渢he whole state of Colorado was under water,鈥� Evanoff explained. 鈥淎nd then we ended up with lowland rivers in the area, and that's where the deposits of dinosaurs occurred.鈥�
Many of those deposits are from the late Cretaceous period, meaning the tail end of the very long age of the dinosaurs. And one of those areas of rich deposits is Weld County.
One day, Ken Carpenter 鈥� who went on to have a storied career in paleontology 鈥� asked his friend Evanoff for a hand in the field. Their destination was the Seven Cross Ranch northeast of Greeley, where they spent the day collecting microfossils.
Evanoff is now a professor of geology at the University of Northern Colorado. He said they had just about wrapped up for the day when Carpenter caught a second wind for another round of prospecting.
鈥淜en's kind of a funny guy. He is very serious when he's out in the field. He doesn't get really excited,鈥� Evanoff recently recalled. 鈥淎nd all of a sudden, he stopped. He looked down and he started jumping around and I thought, hmm, Ken found something.鈥�
It was the tip of the frill of a remarkably intact horned dinosaur skull. Carpenter recognized it from just the small bit of bone visible on the surface.
鈥淪o we sat there for an hour or two just cleaning it up and getting exposed at the surface on that on that day,鈥� Evanoff said.
The next day, they returned with a small crew and a truck to finish the excavation, prepare the skull for transport and haul it away. The specimen they eventually took out of the ground was about four feet long 鈥� small for a species with skulls that usually measure six to eight feet in length. They reasoned that it was from a juvenile animal and looked forward to getting it back to be lab for a closer look.
In 1982, the Seven Cross Ranch was owned by Sonny Mapellli, a civic-minded former state senator and businessman. According to his daughter, Terri DeMoney, Mapelli was usually magnanimous, but the way the paleontologists had handled the fossil rubbed him the wrong way.
鈥淭hey didn't tell them that they were coming 鈥� that they found a dinosaur head. They just came back and took it. And when my dad heard what happened, he got in touch with them and he wanted it back,鈥� DeMoney said.
Mapelli took a lot of pride in his adopted Northern Colorado community. So, when he found himself in possession of a significant piece of the area鈥檚 ancient prehistory on his hands, he decided to donate it to the local government.
鈥淗e wanted it to stay here so that other children and families could all learn about it and actually have something here in Weld County,鈥� DeMoney said.
Triceratops t-shirts were printed for the occasion. There was even a public contest to name it 鈥� 鈥淧ops鈥� ultimately won 鈥� and a declaration making it the official Weld County fossil. The donation came with just one condition: That fossil would remain in Weld County, in a county building, 鈥渟o that all the public could come in and see it,鈥� said Weld County communications director Jennifer Finch.
And that鈥檚 how 鈥淧ops鈥� ended up behind glass, where it remained for decades in the fluorescent-lit lobbies of various Weld County administrative buildings.
By 2018, Pops鈥� glory had faded. The 1980s-era epoxies holding him together were discolored. He had never been fully restored and the whole display was sorely out of date. As Finch describes it, one of the state鈥檚 most prestigious fossils had become background furniture.
鈥淚n a not-so-dignified way, it was how we told people where the restrooms were, 'cause we'd tell them, 鈥楪o out to the lobby, and they're right by the dinosaur,鈥欌�� Finch said.
Resurrection of a fossil
Joe Sertich used to drive up to Greeley to visit Pops when he was an undergrad studying paleontology at Colorado State University. Later, when he became curator of dinosaurs at the Denver Museum of Nature and Science, he would sometimes send his interns and staff to the county offices to look at the skull through the glass.
鈥淭he skeleton and skull of Pops were known by paleontologists for decades, so it's kind of been this unicorn of a dinosaur that's out there that we know is significant,鈥� he said, explaining his fascination. He said there were a couple of details about the fossil that had always bothered him. First, there was its small size. As Sertich explains, 鈥測ou look a little closer, you can tell from the texture of the bone that it is an adult.鈥�
And there was the Laramie rock formation that Pops came out of, which dates to 69 to 70 million years ago. That鈥檚 about 2 million years older than other known Triceratops specimens. All of that raised doubts about Pop鈥檚 identity.
鈥淏ut no one's had access to study because it was in this kind of gray area between museums and hiding up in a in a public facility,鈥� Sertich said.
In 2018, Sertich took advantage of his platform at the Denver Museum of Nature and Science. He reached out to Weld County officials with a proposition. He wanted the county to let him study Pops in Denver. In return, he and his team would return the fossil to Weld County expertly cleaned and restored. County commissioners were excited. They struck a deal.
Old bones, new tricks
Last fall, Sertich and his team made the trip up to Greeley to take measurements and plan out the transport. But he was also on a mission to solve a minor mystery.
鈥淭here were always rumors that there were more pieces in boxes underneath the display,鈥� he said. 鈥淎nd as we move the case away from the wall, it became clear that there wasn't just a single small box. There were four really big bankers boxes loaded basically to overflowing with chunks of dinosaur bone.鈥�
The boxes contained pieces of bone that helped complete the skull. But there were other body parts, too: vertebrae and pieces of tail bone, for instance. Those body parts 鈥� now spread out across counters and carts in the fossil lab 鈥� can fill in some of the blanks in Pops鈥� story.
Paleontologists are finely attuned to the subtlety of bone contours. In the past few months, Pops鈥� contours have come into better focus. A nub of bone on the front of the skull 鈥� a nostril flange 鈥� stood out to Sertich.
鈥淭his big, wide, flat flange is something that you see in Eotriceratops,鈥� he said, referring to an evolutionary precursor to the famous horned dinosaur, 鈥漛ut not so much in a true Triceratops.鈥�
Cleaning the fossil fragments of Pops is slow work, but the team sent this sped up video to show us some of their progress.
— PopsTheTriceratops (@PopsTriceratops)
The team can鈥檛 definitively identify Pops until they鈥檝e finished reconstructing the skull, but just they might have a whole new species on their hands. Sertich said Pops could turn out to be a missing link in horned dinosaur evolution.
鈥淭here are a couple of pages currently missing from that story at different time intervals, and this is one of those missing pages. So, for the first time, we can look at what the world was like 68 or 69 million years ago here in Colorado,鈥� he said.
It will take Sertich and his team a few more months to finish the restoration. They鈥檒l make casts of the skull and publish their findings. Then Pops will be returned with fanfare to Weld County.
Jennifer Finch is looking forward to that day.
鈥淭he skull may come back actually a bit bigger than when it left,鈥� she said. 鈥淎nd if that's the case, we may have to talk about getting a different display case.鈥� And maybe a new location, she says, further away from the restrooms.
Pops is currently at the Denver Museum of Nature and Science, where visitors can watch his restoration in the fossil lab. And because this very old story is also a new one, you can stay up to date on Pops鈥� journey by .
