It’s been more than 200 years since the first dinosaur fossils were scientifically described. Since then, those prehistoric giants have captivated people of all ages, inspiring statues, theme parks and, of course, a film franchise. But a fossil discovery in Montana may upend the way we discover dinosaur bones and who can own them to begin with.

The story starts back in 2006, with a fossil find on a ranch in Montana. Dinosaur bones that are potentially 66 million years old were embedded in rock — horns and bones completely intact.

The find became known as the “dueling dinosaurs,” since the fossils appear to show the dinosaurs were preserved while locked in battle.

Peter Larson, director of the Black Hills Institute of Geological Research, a for-profit fossil preparation and excavation company that helped prepare the find, said an earthquake struck as the dinosaurs fought, sucking them down into the sand at the moment of their deaths. “That’s why they were preserved as complete skeletons and nobody ate them,” Larson said.

The fossilized dinosaurs were a Nanotyrannus lancensis, which is a smaller relative of Tyrannosaurus rex, and a Triceratops horridus, according to Larson. They were found in what’s called a seismite — jagged edges of sedimentary rock — suggesting an earthquake. Larson said this find is special because scientists don’t usually know the cause of death for dinosaurs.

“When you find a dinosaur, you’re looking at a cold case — literally." Peter Larson, director, Black Hills Institute of Geological Research

“When you find a dinosaur, you’re looking at a cold case — literally,” Larson said. “Trying to find the cause of death is almost never possible. But on occasion, you can find some evidence that points to the cause of death. In this particular case, the Triceratops skeleton actually had two Nanotyrannus teeth buried within what would be the flesh envelope, and both of these animals have some skin preserved, as well. So, they’re really, really super important.”

It turned out that many more fossils were found on the same property, including the foot and skull of a Triceratops and a complete T-Rex — potentially one of only a dozen ever found in such condition. But before long, these fossils became entangled in a legal battle that has lasted over a decade.

The issue in question is: Who owns these specimens potentially worth millions of dollars on the private fossil collection market?

Usually, when a fossil is found on private land in the United States, it belongs to the landowner. In this case, the amateur fossil hunters who made the discovery had planned to split the multi-million dollar proceeds from these specimens with the landowner. But the problem is, there wasn’t just one landowner.

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Land in the western US is often divided into surface rights and mineral rights. In the state of Montana, oil and gas companies often own the mineral rights. Historically, it hasn’t mattered. For over 100 years, fossils have been considered part of the surface rights, just like a rock you’d find in your backyard. But in the case of the dueling dinosaurs, the mineral rights holder fought back in court, saying they should own the specimens — because, they say, fossils are minerals.

“[The case] was heard by a three-judge panel and in a split decision, they decided that the fossils were part of the mineral estate, which surprised everybody. ... No one has ever made this claim before, ever. Peter Larson, director, Black Hills Institute of Geological Research

“[The case] was heard by a three-judge panel and in a split decision, they decided that the fossils were part of the mineral estate, which surprised everybody,” Larson explained. “No one has ever made this claim before, ever. There is no place that you can find where fossils have been defined as minerals anywhere, in any statute in any state.”

That means Larson and his team won’t be able to complete the sale of the dueling dinosaurs and the homeowners also miss out on their cut. Fossils are a huge part of the culture for people in Montana, so this decision was a blow to the idea that any homeowner could find and display a fossil they might find in their backyard.

The decision was so unpopular in the state of Montana that Larson’s team successfully filed a petition for a federal re-review of the case. Very few re-reviews are granted, but this one was. So, the case goes back to the Montana Supreme Court to decide.

In the meantime, another debate is playing out: Some paleontologists balk at the notion of selling fossils to begin with.

Related: The dinosaur family tree isn't quite what we thought it was

Jack Horner, a paleontologist at Chapman University in Orange, California, who made some of the most famous paleontological discoveries of the 20th century and served as the technical advisor for all five Jurassic Park & Jurassic World movies, says it doesn’t matter whether or not fossils are minerals, because this court case would mostly just affect commercial fossil hunters, not what he calls real scientists.

For the most part, paleontologists like Horner work on federal land, not private land. The federal government owns both surface and mineral rights on its property and isn’t trying to make money from selling dinosaur bones. In the interest of good science, Horner said, fossil hunting should be paid for by grants, not by selling fossils.

“Commercial collectors are people that go looking for dinosaurs or other fossils to make money, whereas a paleontologist is digging them up for data, so they can publish papers about them." Jack Horner, paleontologist, Chapman University

Horner says paleontologists and commercial fossil hunters have fundamentally different interests. “Commercial collectors are people that go looking for dinosaurs or other fossils to make money, whereas a paleontologist is digging them up for data, so they can publish papers about them,” Horner said. “We’re museums and we don’t really pay money for fossils — we save them. We just take them and save them in the public trust, so they’re for everybody.”

Horner also has some doubts about the dueling dinosaur fossils themselves.

“I don’t know where they geographically came from; I don’t know where they geologically came from; I don’t know their taphonomy — and, basically, that’s all the information a scientist needs,” Horner said. “There’s none of that. So, from a scientific perspective, it is a useless specimen.”

He also questions much of the story behind the fossils, including the earthquake and the cause of death. “We don’t actually know that, do we,” he said. “They haven’t been studied scientifically. We have no idea. Those are the commercial collectors that are saying that.”

Peter Larson disputes this critique of his methods, saying that no one is getting rich from fossil hunting and they took meticulous scientific notes in digging up the dueling dinosaurs.

“Despite what some people may think, this is still a capitalistic society, and it works pretty well,” Larson said. “There are definitely some problems, but people need to be rewarded for their work. This is a way that really fantastic fossils can be found that increases the interest in paleontology, that makes sure paleontologists have a job.”

So — a unique fossil find worth millions of dollars, an unprecedented court case and a scientific debate: Should we even sell fossils to begin with? Either way, the case is in motion and the results will be announced in coming months.

This article is based on a report by Jay Feinstein that aired on Living on Earth from PRX.