The 67-million-year-old centerpiece of Nicolas Cage’s fossil collection was the envy of many a Hollywood A-lister until reports emerged over the weekend linking the fossil to the black market. The Sunday Telegraph reported that a dinosaur skull purchased by Cage at auction in 2007 was provided to auctioneers I.M. Chait by Eric Prokopi, a confessed fossil smuggler currently facing up to 17 years in prison for conspiring to import illicit fossils from China and Mongolia

In lieu of collecting famous works of art, the Oscar-winning Cage seems to have joined a trend among celebrities, royalty, and industrial kingpins of purchasing pieces of natural history. Six years ago Cage won a bidding war against Leonardo DiCaprio to take home his crown jewel, a skull from a Tarbosaurus bataar, for a sum of $276,000, a price befitting the largest prehistoric skull ever to see the auction block at the time.

T. bataar was a fearsome relative of North America’s Tyrannosaurus rex native to modern-day Mongolia. Mongolia’s Gobi desert, where most of the world’s Tarbosaurus skeletons have been found, is a veritable gold mine on the frontier of dinosaur discovery, a paleontological Wild West where countless fossils and new species have been discovered in just the past few years. (Watch Episode 2 of the BBC series Planet Dinosaur for tantalizing details emerging from the earth in that corner of the world.)

Sadly, this renaissance of dinosaur discovery has produced a comparable surge in the black market for fossils stolen out of excavation sites in Asia. The loss of scientific data in these fossil robberies is staggering, as Brian Switek wrote in his piece on Prokopi and dinosaur smuggling for Slate earlier this year. Fossils like Cage’s Tarbosaurus skull are typically excavated and stripped of “almost everything of scientific importance about the animal: how the bones were scattered in the rock where they were found, what preparations were used to clean and reassemble the skeleton, what other fossils were in the same or nearby layers.”

There’s no evidence that Mr. Cage was privy to the illicit origins of his Tarbosaurus skull at the time of purchase, but his hobby endorses a commercial fossil trade overrun with illegal trafficking, to the detriment of the scientific community.

A lot of dinosaur fanatics would probably love to have part of a favorite therapod adorning the mantle, but the cold, hard truth is that dinosaur auctions are to paleontology what poaching is to wildlife conservation. The sale of fossils at auction, across markets from Beverly Hills to eBay, removes valuable clues from the collective picture paleontologists are trying to build of life on Earth 65-plus million years ago. We should honor and protect their method. After all, their breakthroughs bring us closer to real stars—the dinosaur stars of natural history who ruled uncontested for 115 million years, the most dominant group of animals the planet has ever seen.

Mr. Cage, if you really love dinosaurs, donate your collection to a museum where they can be studied. Help bring us closer to that colossally cool world of razor teeth, retractable claws, and thagomizers.