On a tract of public land near Dubois, an extrusion of very old rock — known as the lower Popo Agie Formation — peeks out of a hillside. To the unskilled eye, it just looks like a patch of pinkish-red rocks amid the grassy slopes. 

But in 2013, a team of scientists who specialize in ancient history visited the site and found much more. The extrusion was rife with fossils, enough to keep the scientists busy for the dozen years that have since passed. Along with revisiting the site to look for more samples, the University of Wisconsin Geology Museum team has been doing painstaking work to date the rock and recreate the creatures’ bones that were fossilized there.

What they found is remarkable: North America’s oldest-known dinosaur. The discovery brought scientific advances that revise the understanding of reptile evolution on the planet. It also broke a long scientific naming tradition with a nod to Wyoming’s Indigenous people. 

Meet Ahvaytum bahndooiveche. The dinosaur is slightly larger than a chicken, with a long tail, beaklike mouth and feathers. It lived a very, very long time ago: 230 million years in the past. 

Along with being the oldest known dinosaur found in North America, it’s also the first dinosaur named in the Shoshone language — scientists teamed up with Eastern Shoshone tribal members on the project. 

“So that’s kind of the back side of this story that, to me, is the most important,” said Dr. David Lovelace, a research scientist at the University of Wisconsin Geology Museum who co-led the work with graduate student Aaron Kufner. “And then just the icing on the cake is that the dinosaur itself is a big deal. Scientifically, we didn’t quite recognize how big it was until we got actual radioisotopic ages.”

Bones and stones 

Lovelace grew up in Casper. He originally set out to become a nurse after high school, but Casper College geology professor Kent Sundell opened his world to paleontology, he said, and he never turned back. “I love bones and stones.”  

Once he finished his doctorate, he became a research scientist at the University of Wisconsin Geology Museum. On his very first field season, he took students to the Wyoming site — “a tiny little pocket of exposure that was surrounded by much, much younger rock.” They discovered the Ahvaytum fossils on the ground surface during that first trip.

Such a notable discovery with so little effort is very lucky, Lovelace said. 

But it’s not totally random. Lovelace was driven by a curiosity about the Popo Agie Formation, which he said is “one of the most understudied late Triassic rock units in the U.S.”

Because of factors like access, the Popo Agie is a difficult layer to study compared to other Triassic outcrops, like ones in the desert Southwest, he said. As a result, there is a lot of knowledge about the Southwest rocks and fossils, and not so much about the Wyoming ones. 

“And so even knowing how the Wyoming Triassic correlated, how it is related to those rocks, was not studied at all,” he said. “So that’s been my passion, trying to solve that problem.”

The team found fossils of leg bones on the first prospecting trip, and knew very quickly that it was a dinosaur and Wyoming’s oldest, Lovelace said. But because “nobody knew the age of the Popo Agie,” they didn’t know how ancient it was. 

“It literally had, like a 30-million-year potential range of what it could be,” he said.  “Just off the bat, we had Wyoming’s oldest dinosaur. We knew that that could have been a thing and been pretty cool. But my study, or my interest, is to really dig deep and kind of flesh out the whole story.”

In order to pin down the dino’s age, he said, he and his team needed to precisely date the rocks. It took years of painstaking work to conduct the stratigraphy — the study of rock strata — and analyze the fossils of both Ahvaytum and other species they discovered. Ultimately, the team dated the dinosaur fossil at 230 million years. 

The dino’s age is remarkable because it challenges the mainstream view on how reptiles emerged, with evidence that they were present in the Northern Hemisphere millions of years earlier than previously understood. 

“When we saw that,” Lovelace said, “it kind of blew our minds.” 

What’s in a name 

When publishing about the new dinosaur, Lovelace’s team began going down the traditional path dictated by the International Code of Zoological Nomenclature, which stipulates the use of Latin and character style and often honors a notable scientist.

At the time, there was a lot of social reckoning taking place, Lovelace said, and his team started thinking about the ancestral land where the fossils were discovered. They reached out to their campus tribal liaison, who connected the team with the Eastern Shoshone and Northern Arapaho tribes. 

“That started a partnership that’s still ongoing,” Lovelace said. 

The team worked with tribal elders and school groups, visiting the site together and exchanging knowledge. And in the end, the dinosaur was named in the language of the Eastern Shoshone, whose ancestral lands include the discovery site. Elders like Reba Teran were instrumental in helping identify the terms. 

Ahvaytum bahndooiveche broadly translates to “long ago dinosaur” in the Shoshone language. Several tribal members are named as co-authors in the published work. That includes Teran and Amanda LeClair-Diaz, the Indian education coordinator at Fort Washakie School. 

“The continuous relationship developed between Dr. Lovelace, his team, our school district and our community is one of the most important outcomes of the discovery and naming of Ahvaytum bahndooiveche,” LeClair-Diaz said in a news release. 

“Typically, the research process in communities, especially Indigenous communities, has been one sided, with the researchers fully benefiting from studies,” LeClair-Diaz continued. “The work we have done with Dr. Lovelace breaks this cycle and creates an opportunity for reciprocity in the research process.”

The old way of naming was often divorced from the communities of people connected to the land or species, Lovelace said. “But our philosophy is that it needs to go a lot more beyond just kind of naming it after something. We really want to incorporate that community.”

Diminutive cousin 

Though the dinosaur is small, Lovelace’s team believes Ahvaytum bahnooiveche is likely related to sauropods, a group of enormous herbivorous dinosaurs that included well-known titanosaurs.  

His best guess is that the Ahvaytum lived in a landscape much like present-day coastal Texas, he said, with periods of both wetness and aridity. Although scientists haven’t found its skull material, based on other similar dinosaurs, it was likely omnivorous.

The discovery site has also been a source of fossils for a new species of amphibian, other dinosaur fossils and notable tracks. And, Lovelace said, “there’s still work to be done.”

It goes to show the depth of knowledge that can be gained with some curiosity — even in what appears to be an unremarkable patch of rocky soil in the middle of Wyoming.

“There’s so much history tied up in the rocks,” Lovelace said.