North America's oldest dinosaur is completely rewriting history

Have you ever wondered how and when the fascinating era of dinosaurs began? For decades, paleontologists have been debating this question, armed mostly with fragmented fossil records and theories.

The widely accepted belief is that dinosaurs first originated on Gondwana, the southern portion of the ancient supercontinent Pangea.

For millions of years, their existence was thought to be confined to this region before they gradually spread to Laurasia, the northern part of Pangea.

This theory suggests that dinosaurs established themselves in the south long before leaving any evidence of their presence in the Northern Hemisphere. A remarkable discovery in Wyoming, however, is changing that narrative.

Oldest dinosaur in North America

In 2013, a team from the University of Wisconsin-Madison uncovered fossil remains in the Popo Agie Formation, a region near the equator in ancient Laurasia.

After years of painstaking analysis, the researchers identified the fossils as belonging to a new dinosaur species: Ahvaytum bahndooiveche.

This dinosaur, estimated to be 230 million years old, is now the oldest known dinosaur from Laurasia, challenging the idea that dinosaurs only thrived in the Southern Hemisphere during this time.

Dr. Dave Lovelace, a scientist at the UW Geology Museum, emphasized the significance of the discovery. “We have, with these fossils, the oldest equatorial dinosaur in the world – it’s also North America’s oldest dinosaur,” he said.

Laurasia, North America, and dinosaurs

Laurasia was one of two supercontinents that formed during the late Paleozoic and early Mesozoic eras. It was made up of what are now North America, Europe, and Asia.

Around 200 million years ago, Earth’s landmasses were all connected as part of a giant supercontinent called Pangaea. Over time, Pangaea started to break apart, and Laurasia emerged as the northern part of the split.

While it was a vast landmass, it wasn’t just one giant chunk of land – it was split into several regions that would eventually evolve into the continents we know today.

As Laurasia broke apart and drifted into its current position, it played a major role in shaping the world’s geography.

The separation of Laurasia from the southern supercontinent, Gondwana, led to the creation of the Atlantic Ocean, which opened up between North America and Europe.

The shifting of Laurasia also influenced global climates and ecosystems, setting the stage for the diverse life forms that would appear in the following millions of years.

Characteristics of the dinosaur fossil

Far from the towering giants of later eras, Ahvaytum bahndooiveche was modest in size.

“It was basically the size of a chicken but with a really long tail,” Dr. Lovelace explained. Measuring just over one foot tall and three feet long, this early dinosaur likely lived an omnivorous lifestyle, similar to its sauropod relatives.

Although the fossil record for Ahvaytum bahndooiveche is incomplete, the team’s research places this species in a critical period following the Carnian pluvial episode.

This climatic event, which occurred 234 to 232 million years ago, drastically altered the environment – turning vast, arid deserts into lush and fertile landscapes.

These changes created more hospitable habitats, which likely played a key role in encouraging the diversification and spread of early dinosaurs. The period marked an important chapter in dinosaur evolution, as species began to adapt to these new and thriving ecosystems.

Timeline of dinosaur evolution

Using high-precision radioisotopic dating, the scientists determined that Ahvaytum bahndooiveche lived in Laurasia about 230 million years ago, making it one of the oldest known dinosaurs from the Northern Hemisphere.

Older tracks in the same region suggest that dinosaur-like creatures were present there even earlier, challenging previous beliefs that dinosaurs originated solely in the Southern Hemisphere before spreading northward.

This discovery not only alters the timeline of dinosaur evolution in North America but also highlights a significant collaboration with the Eastern Shoshone Tribe.

The species’ name, Ahvaytum bahndooiveche, meaning “long ago dinosaur,” honors the Indigenous people whose ancestral lands were home to the fossil site.

This partnership reflects a deeper respect for cultural heritage, integrating Indigenous language and perspectives into the scientific process.

New model for research

Amanda LeClair-Diaz, an Eastern Shoshone and Northern Arapaho tribal member, highlighted the importance of this partnership.

“The continuous relationship developed between Dr. Lovelace, his team, and our community is one of the most important outcomes of this discovery,” said LeClair-Diaz.

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

A legacy of collaboration

The discovery of Ahvaytum bahndooiveche holds significance beyond just expanding our scientific knowledge. It challenges long-held beliefs about dinosaur origins and encourages scientists to rethink established theories.

Additionally, this finding highlights the value of incorporating diverse perspectives in research.

By collaborating with the Eastern Shoshone Tribe in naming the dinosaur and respecting the cultural heritage of the land where the fossils were found, the project sets a new standard for inclusive and ethical scientific practices.

This small dinosaur not only revises our understanding of prehistoric history but also promotes a more respectful and collaborative approach to scientific discovery.

The study is published in the Zoological Journal of the Linnean Society.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–