Researcher Matt Mossbrucker believes four small dinosaur tracks found within sight of the skyscrapers of downtown Denver were made by two stegosaurus babies, a find he says would be "incredibly rare."
Some other researchers agree the tracks were left by stegosaur toddlers, but still others have their doubts.
Mossbrucker, director of the Morrison Natural History Museum, said the half-dollar-size tracks were discovered in the foothills just west of Denver last year, but it took time and digging for him to conclude they were made by stegosaur babies.
The tracks, reported this week by The Denver Post, were found not far from the site where the first known stegosaur bones were unearthed 130 years ago.
Little is known about stegosaurs except that they were plant-eaters and grew to weigh about six tons.
Because their feet were relatively small, their tracks are hard to find, and as a result little is known about how quickly they grew, how long they lived and how they survived as well as they did in a time and place where plants were scarce.
Baby footprints, combined with the bones and another adult imprint already at the Morrison museum, could help answer some of those questions.
Paleontologist Robert Bakker, a curator at the Houston Museum of Natural Science and volunteer curator in Morrison, agrees with Mossbrucker that the newly analyzed prints are those of stegosaurus babies.
Finding such imprints in the vicinity of the earlier discovered bones is something that, "as a rule, never happens," he said.
"It's incredibly rare," Mossbrucker said. "I don't even want to think about the possible monetary value."
Ken Carpenter, a curator at the Denver Museum of Nature and Science, had not seen the tracks in person but said he was wasn't convinced they were from stegosaurus babies.
"There were a lot of other dinosaurs running around at that time, certainly with these with these three toes and small, wide feet. It could be one of those other types. Let's just say the verdict is still out," he said.
Kirk Johnson, vice president of research at the Denver Museum of Nature and Science, said he doesn't question the legitimacy of the find as much as the significance.
"At the end of the day, I wouldn't call it a huge scientific discovery because we know to expect tracks," he said. "It's not adding a huge amount of information."
Mossbrucker said most discoveries of dinosaur fossils and tracks are in rural or remote areas, Mossbrucker said. Paleontologists often ignore sites like Morrison, a little more than 10 miles from Denver, he said.
"I think because these sites are so close to the Denver metro area, they often get overlooked for more appealing, exotic sites," he said. "But why would I want to go to China or Patagonia when I have this type of geology right here?"
"For anyone who is interested in paleo-ecology, this is going to be an interesting site."