It’s more than six-feet long and weighs over 200 pounds. A relic left behind by one of the largest predators to ever walk the earth, and it could be yours for the right price.

This fossilized skull of a Tyrannosaurus rex was found on private land in South Dakota. Nicknamed “Maximus,” the bones are expected to sell for around $20 million at auction next month. While that could make Maximus one of the most expensive fossils ever, its sale is also raising concerns about the future of an industry that made discoveries like this possible.

The controversy began 25 years ago, when a T-Rex nicknamed “Sue,” found on the same site as Maximus, became the first dinosaur to ever be auctioned off, selling for over $8 million. Paleontology experts at the time expressed concerns that future sales would make it harder to carry out excavation work on private land. Only a year after Sue was purchased, Paleontologist John Hoganson described the challenges collecting fossils on private property because of the growing market for them.

“In many areas where dinosaur fossils are found, it is becoming more difficult for professional paleontologists to obtain permission to collect fossils on private property because of the commercial value of fossils,” wrote Hoganson in a 1998 edition of the North Dakota Geological Survey’s newsletter.

The Society of Vertebrate Paleontology has since argued that fossil specimens sold to private collectors are lost to science. They have stated that the high-profile auctions of vertebrate fossils “shouldn’t happen” and have lobbied for the cancellations of several sales.

“Fossils are fascinating and beautiful objects,” wrote the organization. “As paleontologists, we share the wonder, but when significant fossil specimens are held by individuals and not public institutions, society loses.”

Meanwhile, auctioneers maintain the money brought in by prehistoric remains could be life changing to the owners of farms and ranches where they are discovered. A velociraptor skeleton was bought for nearly $12.5 million just this year, while a mostly complete T-Rex fossil sold for over $30 million in 2020.

The auction of Maximus is set for December, while in the meantime the debate continues over private sales – and the impact they have.