(CNN)An approximately 300 million-year-old fossil skeleton discovered at Canyonlands National Park in Utah could be the first of its kind, researchers say.
The exact species and classification have yet to be determined, but the fossil is a tetrapod -- meaning animal with four legs -- and could be an early ancestor of either reptiles or mammals. Paleontologists have determined the fossil could be anywhere from 295 million to 305 million years old, between the Pennsylvanian and the Permian geologic time periods.
"It's a phenomenal specimen. You do not see something like that very often, so it's really significant for that in itself," said Adam Marsh, lead paleontologist at Petrified Forest National Park in Arizona. "But what it indicates is that there's probably more fossils out there, especially at Canyonlands, in this really important time interval."
A team of scientists and paleontologists from Petrified Forest, the Natural History Museum of Utah and the University of Southern California helped collect the fossil from Canyonlands.
The fossil was found as a complete skeleton, and the bones were in their "life positions," meaning the same position as when the animal was alive.
This fossil appears to be an early amniote, which is a land-living vertebrate that lays eggs, according to Adam Huttenlocker, an outside specialist on the team who researches early tetrapod fossils and is an assistant professor at USC. The complete skeleton allows scientists to analyze the evolution of amniotes, in addition to the ancestors of early reptiles and mammals.
This area of Canyonlands hasn't produced amniote fossils in the ancient rock formation the fossil was found in, so Huttenlocker said there's a good chance this fossil represents a new species of early amniote.
The fossil excavation of a lifetime
A park ranger at Canyonlands reported the fossil around October 2020. After the research permit was processed, the team collected the fossil a year later, on October 23 of this year.
Matthew Van Scoyoc said this was the first time he's seen anyone apply for a research permit to extract a fossil in his four years as the research coordinator of the National Park Service's Southeast Utah Group, which includes Canyonlands. He coordinates research and provides permits for these parks, but excavating hasn't been a part of the job -- until now.
"I never thought I'd get to go on a fossil excavation in my life, and that was just really, really cool," Van Scoyoc said.
The excavation took an entire day, Van Scoyoc said. The team hiked 13 miles roundtrip into the backcountry, extracted the fossil in two pieces and hiked back with a skeleton in their backpacks. (The fossil's original location, Lost Canyon, is designated as a wilderness area by the National Park Service, so no motorized vehicles were allowed.)
The fossil is now at the Petrified Forest fossil preparation lab for tests and scans of the skeleton and skull. After scientists determine the species, which could take at least a year, Marsh said the fossil will remain with the National Park Service for further research and museum exhibits.
There is a possibility that this fossil is a new species, which is rare -- Marsh said some paleontologists go their entire careers without a discovery of that kind. But even if the fossil turns out to be a known species, Marsh said this finding is still significant for understanding the biodiversity of that time.
Fossil specimens from aquatic animals like shark spines are common finds at Canyonlands, especially along the river, but Huttenlocker said this is the first time he has been notified of a land-living vertebrate fossil.
"This is a rare, once-in-a-lifetime opportunity for me," Huttenlocker said.
'Scraping the surface'
The fossil was at risk for erosion from rain and water, which is why Van Scoyoc said they issued the permit. Canyonlands does not have any paleontologists on staff, so they outsourced paleontologists from Petrified Forest, which is known for its fossils.
"Fossils themselves are probably not that rare in Canyonlands. It's just, we haven't looked for them thoroughly," Van Scoyoc said. "What'