A chicken-sized dinosaur discovered in Wyoming has upended scientists’ understanding of when these ancient reptiles first appeared in North America, pushing back their arrival by millions of years. The finding challenges long-held beliefs about how dinosaurs spread across the ancient world.
A Tiny Pioneer
“We have, with these fossils, the oldest equatorial dinosaur in the world — it’s also North America’s oldest dinosaur,” explains Dave Lovelace, a research scientist at the University of Wisconsin Geology Museum who co-led the research published in the Zoological Journal of the Linnean Society.
The diminutive creature, named Ahvaytum bahndooiveche, lived approximately 230 million years ago in what is now Wyoming, though at the time the area was near the equator on the ancient supercontinent of Laurasia.
Small Size, Big Implications
“It was basically the size of a chicken but with a really long tail,” Lovelace notes. “We think of dinosaurs as these giant behemoths, but they didn’t start out that way.” At full size, the creature stood just over one foot tall and measured about three feet from head to tail.
Changing Scientific Understanding
“We’re kind of filling in some of this story, and we’re showing that the ideas that we’ve held for so long — ideas that were supported by the fragmented evidence that we had — weren’t quite right,” Lovelace says. “We now have this piece of evidence that shows dinosaurs were here in the northern hemisphere much earlier than we thought.”
A Climate Connection
The discovery is tied to a significant period of climate change known as the Carnian pluvial episode, which occurred between 234 and 232 million years ago. During this time, previously inhospitable desert environments transformed into more habitable areas, potentially enabling dinosaurs to expand their range.
Breaking New Ground in Scientific Collaboration
The discovery marks more than just a scientific milestone. For the first time, a dinosaur species has been named in the Eastern Shoshone language, acknowledging the Indigenous peoples whose ancestral lands yielded these important fossils.
“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,” says Amanda LeClair-Diaz, a member of the Eastern Shoshone and Northern Arapaho Tribes who co-authored the paper.
“Typically, the research process in communities, especially Indigenous communities, has been one sided, with the researchers fully benefiting from studies,” LeClair-Diaz explains. “The work we have done with Dr. Lovelace breaks this cycle and creates an opportunity for reciprocity in the research process.”
Looking Forward
The discovery not only reshapes our understanding of dinosaur evolution but also sets a new standard for how paleontological research can be conducted in partnership with Indigenous communities. The name Ahvaytum bahndooiveche, meaning “long ago dinosaur” in the Shoshone language, stands as a testament to this collaborative approach to scientific discovery.