Paleontologists at the University of Wisconsin-Madison conducting a study on a dinosaur fossil say that it radically challenges our understanding of the origin and spread of dinosaurs. The new investigation into the fossil, found in 2013 and dubbed “North America’s oldest dinosaur,” is rewriting the story of the dinosaurs that once ruled the Earth.
The study, published in the Zoological Journal of the Linnean Society, relates to the fossil of a 230-million-year-old chicken-sized dinosaur called Ahvaytum bahndooiveche. The study’s researchers say that the age of the fossil, and the location in which it was found, suggests that dinosaurs existed in the Northern Hemisphere millions of years earlier than previously believed.
New study into ancient fossil rewrites dinosaur origin story
Until the research team made their discovery and compiled their data, paleontologists believed that dinosaurs first emerged in the southern part of the super-continent Pangea, in a place called Gondwana, before spreading out to the northern half of the continent. The study of the Ahvaytum bahndooiveche fossil has challenged this belief, and serves as evidence that the dinosaurs were in the northern hemisphere much earlier than previously thought.
“We have, with these fossils, the oldest equatorial dinosaur in the world – it’s also North America’s oldest dinosaur,” said Dave Lovelace, a research scientist at the University of Wisconsin Geology Museum, who co-led the study.
According to Aaron Kufner, the co-lead of the steady, what is intriguing about the findings is the accuracy with which they have confirmed the age of the fossil. While scientists have found fossils in other areas which have also turned out to be older than initially thought, the new Ahvaytum bahndooiveche fossil has the most precise proven age.
“The interesting aspect of this animal is the time and place of its occurrence,” Kufner told Newsweek. “Some other researchers have suggested that some dinosaur-bearing deposits from the U.K. are older than originally thought and possibly contemporaneous with the site we have presented. However, the age control on these sites is less precise than what we have now for the Popo Agie Formation.”
The team did not find a complete fossil, a rarity in itself, but they did find a large enough fragment to determine that Ahvaytum bahndooiveche was an individual species of dinosaur. The dinosaur is believed to be a relative of the Sauropods, which is a group of herbivore dinosaurs that included the Tyrannosaurus rex. The creature was way smaller than its Saurapod relatives, which were known for growing to extremely large sizes, proving that dinosaurs were not always huge.
“It was basically the size of a chicken but with a really long tail,” said Lovelace. “We think of dinosaurs as these giant behemoths, but they didn’t start out that way.”
The researchers conducted high-precision radioisotopic dating of rocks in the formation that held the fossil remains, which revealed the age of the fossil and catalysed researchers to re0evaluate their understanding of dinosaurs and their evolution.
“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,” said Lovelace. “We now have this piece of evidence that shows dinosaurs were here in the northern hemisphere much earlier than we thought.”