When I was a fossil-crazed kid, all I wanted was my very own dinosaur. A living one, like a small apatosaurus I could ride to school, was what I desired most, but I would have happily settled for a fossil one. As I’ve grown older and helped palaeontologists dig up ancient bones around the American west, though, I’ve had a change of heart. The living room is no place for any dinosaur, and I fear that is where a juvenile allosaurus due for auction might end up.

Summers Place Auctions, in West Sussex, which hopes to sell the Jurassic-era skeleton in November, has provided precious few details about the dinosaur. The bones were found in 2007 at Wyoming’s Dana quarry, but, while advertised as “almost complete” the official ads don’t disclose what that actually means in terms of which parts have been reconstructed or fixed up in their reconstruction. What they do know is that the skeleton is expected to fetch upwards of £300,000 from whoever digs deepest for the bones.

It’s heartbreaking to watch. The allosaurus might hold secrets as-yet-untold about how these fearsome carnivores lived back when Wyoming was a fern-covered floodplain that hosted a fantastic menagerie of Jurassic giants. There is a chance that a museum might pick up the fossil and, hopefully, the geologic data from its excavation that are critical to investigating prehistoric life, but such specimens are at risk of slipping away into private hands where they will stand, useless, as they collect dust in someone’s parlour.

Lindsay Hoadley of Summers Place Auctions prepares the allosaurus skeleton. Photograph: Gareth Fuller/PA

The usual response to such criticism is to ask, “Don’t palaeontologists have enough dinosaurs already?” Allosaurus was named by palaeontologist Othniel Charles Marsh way back in 1877. Its name is derived from the Greek for “different lizard”, and it’s the most common large, predatory dinosaur found in late Jurassic rocks that span from Mexico through the Four Corners area of the United States, as well as a few occurrences in Portugal. At one particular site in eastern Utah – the Cleveland-Lloyd dinosaur quarry – palaeontologists have extracted the bones of more than 48 individual allosaurus representing a wide span of life stages. Is it really that bad if the scientists lose one skeleton to someone in search of a status symbol?

But such questions reflect a misunderstanding of what palaeontology is all about. The science isn’t restricted to finding and describing ancient species, as if palaeontologists are glorified stamp collectors. The goal of the discipline is to reconstruct and understand life as it was in various chapters in Earth’s history. The more fossils palaeontologists have, the finer the resolution on our window into Deep Time.

Every allosaurus skeleton – every bone and tooth, even – provides new data for two species of the dinosaur that ranged far and wide between 155 and 148m years ago. And each of those fossils comes from a distinct individual that had its own life history. To understand how these dinosaurs grew up, how they varied from one to the next, and how they evolved, palaeontologists need all the fossils they can get their hands on. This is not to say that there should be a blanket ban on all fossil sales and private collection. Plucking up a little ammonite from the beach is a thrill, as I found myself during a visit to Charmouth – the gateway to England’s Jurassic Coast in Dorset – earlier this year. Giving a chunk of petrified wood to a prehistory-crazed child is a way to give them a direct connection to the past. But we’ve been too lax about letting scientifically important fossils be ushered away into uselessness by those looking for a conversation piece. A Rolex or a Maserati is a status symbol. That’s what they were made for. But not an allosaurus. Given that our mammalian ancestors scurried beneath the feet of the dinosaurs, it is part of our own backstory.

Unless there’s a major change in fossil collection policies, such sales will continue. Laws that protect the natural history heritage of countries such as Mongolia and Brazil are unlikely to fit into the tense history of land rights in the American west. But I hope that collectors and palaeontologists can somehow work together to make sure that every significant fossil is properly collected, documented, and registered. If those fossils eventually make it back to the public through donation or sale, as sometimes happens, the critical information about where that fossil came from and how it fits into the history of life will remain intact.

All the same, I’m saddened to see part of my country’s Jurassic heritage go up for sale to the highest bidder. The allosaurus is an animal that records the details of a lost world in its bones. That’s priceless.