In early April, a paleontology graduate student, Robert DePalma, published a major find in The Proceedings of the National Academy of Sciences and hyped the discovery in The New Yorker. Locked in layers of North Dakota rock, he had found an impressive collection of ancient fish, microorganisms and plants that date to the same time period as the infamous global extinction event that killed the dinosaurs. That extinction is widely believed to have been caused by an asteroid impact, and DePalma’s site seems to offer further evidence supporting that theory.

But behind the discovery lurked an uncomfortable question: Who should own a fossil? DePalma’s dig site — which he called Tanis after the real ancient Egyptian city depicted in “Indiana Jones and the Raiders of the Lost Ark” — is on privately owned ranchland. That allowed him to sidestep bureaucratic red tape and set contracts that give him perpetual control over the management of any fossils from the site — even those that end up being given or sold to museums and research institutions. Those contract clauses are an unprecedented arrangement, according to other paleontologists, and they mean that the Tanis finds bump up against some bigger debates about fossil ownership. Turns out, where you dig matters almost as much as what you find there.

The central issue is one that should be familiar to any Indiana Jones fan: Where does a specimen belong once it has been dug up? In 2009, Congress passed the Paleontological Resources Preservation Act, a law that comes down squarely on the side of “in a museum.” Under the law, most fossil digging on federal lands requires a permit, those permits can only be obtained by qualified scientists, and any specimens that are found belong to the public. Scientists at accredited museums and research centers get first dibs.

But none of that applies on private land, said Thomas Carr, senior scientific advisor at Wisconsin’s Dinosaur Discovery Museum and director of the Institute of Paleontology at Carthage College. There, both access to the land and ownership of the fossils usually go to whoever is willing to pay landowners the most, he told me. And that often means commercial fossil hunters who sell specimens to private collectors rather than museums and research institutions.

That makes a difference because, like all scientists, paleontologists are supposed to ensure that their work can be reproduced. For a fossil to be scientifically valuable, both it and its geologic context need to be carefully documented, and it has to remain accessible to future scientists who want to re-examine and reinterpret it. And that’s not always possible with fossils that come from private land.

In some cases, landowners might not have much incentive to give anyone access to fossils at all, said J.P. Cavigelli, museum collections specialist for the Tate Geological Museum at Wyoming’s Casper College. For instance, a lot of fossils in the eastern part of the United States are found in quarries. Cavigelli told me about visiting a quarry in North Carolina and seeing a beautiful exposed layer rich with fossils. But the value to the quarry owners was in the rock, not the specimens. “In the last few years, they just blew through that whole layer,” he said.

In other cases, fossil hunting on private lands means important fossils become interior decoration rather than science. Carr lamented the loss of “Samson,” one of the most complete Tyrannosaurus rex skeletons ever found. It last sold for around $5 million in 2009, to a private buyer who wanted their identity kept secret. “It’s virtually perfect, and it’s gone. The skull is in the lobby of some company somewhere,” Carr said. And while Samson has been put on public display before, Carr said that the lack of contextual information and the fact that it isn’t being kept in a museum or research facility makes it virtually useless to science. “Even if I knew where it was now, I wouldn’t make the effort to study it,” he said.

But while some scientists, like Carr, are generally opposed to doing paleontology on private land, Tanis isn’t the only professional, scientific dig happening beyond the public’s reach. Cavigelli gets most of his specimens from digs on private land, for instance. And Pat Leiggi, director of paleontology at the Museum of the Rockies in Montana, told me that about 20 percent of the digs his museum is involved in happen on privately owned land or land owned by a state, where the laws governing digs on federal lands don’t apply.

Nobody knows exactly how much paleontology is done on public lands versus private lands, partly because profiteers who dig on private land and sell what they find don’t have to tell anyone what kinds of specimens they have delivered to private collections. But Carr has done some back-of-the-envelope calculations of how paleontology on private land affects access to Tyrannosaurus rex specimens. By Carr’s estimate, there are about 34 T. rex specimens in private hands. In a recent study he did on T. rex bone growth, Carr worked with 46 specimens, ranging from a complete skeleton down to individual bones. “If all those privately owned T. rexes were available, my sample size would leap to nearly 80,” he said.

Digs on private land also raise ethical complications about whether to treat fossils as a natural resource commodity that you’d pay landowners for, or as a piece of universal scientific heritage. For example: Should scientists pay landowners? Cavigelli does — first in “trespass fees” for exploratory digging and then, if any spectacular specimens are found, he writes up a separate agreement to compensate the landowners for taking the find to a museum. In one case, a mammoth was worth a tax write-off. In another, Cavigelli paid a landowner for a T. rex find. “They would have made more from a private collector,” Cavigelli said. “But they also wanted it to stay here and be on public exhibit. There are other landowners who want too much [money], and we don’t deal with those guys.”

Leiggi, in contrast, won’t deal with anyone who wants any money. He sees that as a violation of the Society of Vertebrate Paleontology’s ethics rules, though the rules allow scientists to make payments if they bring a specimen into public trust. “I tell my staff we do not and will not ever get involved in that,” he said.

These kinds of disagreements contribute to professional skepticism of the Tanis site and the specimens found there. DePalma didn’t respond to requests for an interview, but Carr and Cavgelli both said they were troubled by the ownership stipulations in the contract described in the New Yorker article because it’s not clear how these types of ownership clauses would be used. For instance, both scientists worried about the possibility that DePalma could give or sell a fossil to a museum and, later, take it back, removing the specimen from the scientific purview. Landowners have tried to take back fossils donated to museums often enough that Cavigelli and Leiggi have to specify in writing that that isn’t possible. More broadly, the clauses add uncertainty to the already complicated world of fossil ownership. With a site that’s likely to be a big deal in science for years to come, that confusion could create a mess almost as big as an asteroid crashing to Earth.