A recently surfaced and extremely complete dinosaur fossil dubbed Juliasaurus just marked its first public appearance in Colchester, the U.K. The 154-million-year-old theropod’s species, however, remains a mystery.

The 20 foot-long Juliasaurus, which would have weighed just over 1,300 pounds in its heyday, initially turned up in 2020 in Wyoming’s Late Jurassic-era Morrison Formation—one of the most notorious hotbeds for digging up dinosaur fossils in the world. The experienced dino dealers at the London-based natural history and antiquities gallery David Aaron sold the specimen to a private collector two years ago. Rumor has it that the skeleton is now named for a relative of its new owner.

David Aaron gallery also brokered the fossil’s loan this year to Colchester’s Hollytrees Museum, situated inside an 18th-century Georgian townhome. Juliasaurus will remain on view at the institution through November as part of “Discover: Museum Wonders,” an exhibition of local historical artifacts organized to celebrate the first time that a dinosaur has ever appeared in Essex county’s second-largest city.

Juliasaurus on view at Hollytrees Museum. Photo by David Owens, courtesy of David Aaron Gallery.

With time, it’s possible that Juliasaurus might introduce scientists to an entirely new species of dinosaur—like the Tuebingosaurus maierfritzorum discovered in 2022 and the Vectidromeus insularis discovered one year later.

At first, experts believed that Juliasaurus was an Allosaurus, an iconic carnivore with two recognizable crests on its snout that predated the Tyrannosaurus Rex by approximately 90 million years. Or, perhaps Juliasaurus was a smaller bipedal carnivore, the Marshosaurus. Alas, several anomalies arose upon further comparison between Juliasaurus and identified examples of its two suspected species—namely regarding the newfound creature’s skull, its pelvis, and the air sac structures within its vertebrae.

Paleo artwork of Juliasaurus. Photo: Mark Witton.

Scientists are, of course, eager to study Juliasaurus further. The rapidly expanding industry of private dinosaur fossil sales has already caught heat for robbing the experts of such opportunities. David Aaron, however, is working towards forging solutions. Last year, the gallery facilitated the discovery of the small late-Jurassic Enigmacursor herbivore by presenting another mysterious dinosaur fossil that didn’t quite fit its initial classification of Nanosaurus to the National History Museum in London. That institution subsequently secured a private donor to buy the dino and gift it to them for further examination.

“The display at Colchester will coincide with the opportunity,” the museum noted in press materials, “to undertake scientific research into the fossil for the first time.”