“Unearthing History: UW-Madison Researchers Reveal North America’s Ancient Dino Past”

With the identification of a new dinosaur species, scientists at the University of Wisconsin–Madison have disputed a long-standing theory regarding the origins of dinosaurs and their distribution across the Earth.

They disclosed their results on January 8 in the Zoological Journal of the Linnean Society.

A scientific hypothesis proposed that dinosaurs first arose in the southern region of the supercontinent Pangea, remaining for millions of years before moving northward. This theory was derived from the lack of fossils in the north that were congruent in age with those from the south, according to the authors of the study.

“Just because we didn’t uncover dinosaurs doesn’t imply they weren’t present,” remarked Paleontologist Dave Lovelace, a researcher at the University of Wisconsin Geology Museum and principal investigator of the study.

Lovelace and his team recently unveiled their discovery of the oldest dinosaur in the northern hemisphere: Ahvaytum bahndooiveche.

His team invested years examining fossils from this new, chicken-sized dinosaur, which were unearthed in contemporary Wyoming in 2013. The researchers concluded that the fossils were approximately 230 million years old, which aligns with the time frame of the earliest dinosaurs discovered in the southern hemisphere, Lovelace mentioned.

“The bone, the creature itself, is relatively minor. It doesn’t seem significant,” Lovelace stated. “However, the location and time period of this discovery, in relation to the geological timeline, is crucial to the narrative of dinosaur evolution.”

Their discovery indicates that dinosaurs inhabited both northern and southern hemispheres simultaneously. It also raises questions about whether dinosaurs originated in the south at all.

“So essentially, it shows that by the time dinosaurs appear in the fossil record, they exhibit a fairly global distribution,” Lovelace articulated.

Lovelace and his group examined the fossils and the surrounding soil to assess their age and provenance. They investigated the characteristics and arrangement of crystals in a rock layer above the fossils to establish their date.

“Congratulations on the discovery,” declared seasoned paleontologist Paul Sereno, a professor at the University of Chicago who did not participate in the research. “I find the fossils incredibly intriguing and it highlights that small dinosaurs were roaming both the north and south approximately 230 million years ago.”

Approximately 35 years prior, Sereno contributed to the discovery of some of the earliest dinosaur fossils in Argentina.

“The notion that dinosaurs originated in the south and later migrated north, or had some point of origin in South America or the Andes — I personally never subscribed to that belief,” Sereno commented. Ultimately, the fossil record is inconsistent, he added.

“Paleontology is like this slowly leaking Pandora’s box that continues to provide new insights,” Sereno expressed.

In fact, dinosaurs may have existed even earlier.

“We’ve discovered upright footprints that predate both my dinosaurs and those found in Wyoming,” Sereno stated. “We have footprints which we suspect belong to dinosaurs, potentially the earliest ones at 250 million years.”

What did it look like?

Ahvaytum bahndooiveche was about the size of a chicken, as inferred from fossils of its ankle and part of its femur.

“Just those two bones reveal a significant amount about this creature,” Lovelace noted. “It’s relatively compact, standing just over a foot high at the hips, and would have measured around two to three feet in length. It had a very long tail and a reasonably lengthy neck, but overall it was not very large.”

Additionally, based on Ahvaytum’s lineage, it was likely an omnivore, he noted.

The name Ahvaytum bahndooiveche, meaning “long ago dinosaur,” was coined by study author Reba Teran, a member of the Eastern Shoshone Tribe. The site in Wyoming lies within their ancestral lands.

“The fact that the creature carries the first Shoshone designation for an animal is particularly meaningful,” Lovelace concluded.