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Scientists find a 'dinosaur bonanza' during Yukon River trip

Paleontologists Tony Fiorillo and Yoshitsugu Kobayashi make notes after discovering a dinosaur footprint along the banks of the Yukon River.
Emily Schwing/KYUK
Paleontologists Tony Fiorillo and Yoshitsugu Kobayashi make notes after discovering a dinosaur footprint along the banks of the Yukon River.

A small team of researchers is on the Yukon River this month to learn more about an area where dinosaur footprints were discovered 10 years ago. And in a single week, they’ve turned up at least two dozen footprints left by at least five different ancient species.

Halfway into the second day along the Yukon River, the team is more than 300 miles west of Fairbanks, near Nulato. Paleontologist Tony Fiorillo points to two small blobs protruding out of a large block of yellow sandstone. They look like flattened tennis balls, except there are three distinct toes. These are 100 million year old dinosaur footprints.

“So it’s either another body size of a dinosaur that lived here or it’s a baby,” Fiorillo said.

Fiorillo is the Executive Director of the New Mexico Museum of Natural History and Science. He said that this print was made by an ornithopod, a group of bipedal herbivores. This is the smallest ornithopod print he that said he’s ever found.

A three-man team of scientists are traveling the middle section of the Yukon River by boat with a local guide this summer. They're looking for signs of dinosaurs that once roamed here during the early Cretaceous Period, which was around 100 million years ago
Emily Schwing/KYUK
A three-man team of scientists are traveling the middle section of the Yukon River by boat with a local guide this summer. They're looking for signs of dinosaurs that once roamed here during the early Cretaceous Period, which was around 100 million years ago

The leader of a three man team, Fiorillo also discovered signs of an ancient fish species. He pointed to a gray block of sandstone with marks that look like someone scraped their fingernails across it. There are a series of three evenly spaced, raised lines.

“What this surface is is an ichnogenus called undichna, a trace fossil of a fish, a bony fish,” Fiorillo said. “As the fish is swimming and it’s fins are hitting the bottom, the rays of the fin will do that.”

Between 2000 and 2013, Fiorillo, who is an expert on the dinosaurs that once roamed Alaska, visited the upper reaches of the Yukon River six times. During those years he only ever found two dinosaur footprints.

“That’s the hardest I ever worked for two footprints,” Fiorillo said.

But now, on the middle section of the river, Fiorillo said that it’s something of a "dinosaur bonanza."

“I think it might have taken an hour to find the first footprint. I wouldn’t say the floodgates are open yet, but I think we’re gonna feel like that at the rate we’re finding stuff,” Fiorillo said.

By the end of the second day of field work, the three-man team had recorded nearly a dozen fossil footprints. In the following few days, that number has more than doubled and the team plans to continue their search through the middle of August.

Emily Schwing is a long-time Alaska-based reporter.