A Utah parking lot exposed 150-million-year-old dinosaur fossils. Bones and surrounding rock weighing 3,000 pounds were excavated.

Yes, a parking lot is common, but a dinosaur underneath isn’t. Construction work on this Utah parking lot was paused for an eerie reason.

Parking lot construction at Dinosaur National Monument was halted after asphalt removal exposed fossils, identified by park staff on September 16, 2025. This marked the first fossil excavation since 1924 at this location. The monument itself was established in 1915.

Soon after, paleontologists were allowed to assess and excavate the fossils, which most likely belonged to Diplodocus—a large, long-necked dinosaur.

What was Diplodocus?

Diplodocus was first scientifically described in 1878.

Fundación Conjunto Paleontológico de Teruel-Dinópolis describes it as one of the most recognizable dinosaurs in popular culture. The foundation writes:

“Since the beginning of the 20th century, replicas of its skeleton have been exhibited in major natural history museums around the world, making it a symbol of global paleontology. Its presence in exhibitions and audiovisual productions about dinosaurs has contributed to making it one of the best-known ‘terrible lizards’ among the general public.”

When Diplodocus lived in Utah

These dinosaurs roamed present-day Utah around 150 million years ago, during the Late Jurassic Period. Back then, the area was warm and semi-arid, with streams and floodplains, rather than the landscape visitors see today, according to the National Park Service. The NPS also suggests that the quarry’s fossil-bearing sandstone was part of an ancient river channel and that droughts likely killed animals living around the river. Returning floods then transported their bones, and sediment subsequently buried the remains.

Excavation details

During 1909-1922, excavations at this site were led by the Carnegie Museum. The Smithsonian National Museum of Natural History and the University of Utah excavated the location in 1923 and 1924, respectively.

Between mid-September and mid-October 2025, around 3,000 pounds of fossils and surrounding rock were excavated. The announcement was published on the NPS website on January 16, 2026.

In that announcement, the National Park Service said the remains were housed at the Utah Field House of Natural History State Park Museum in Vernal, Utah. It added: “The work can be viewed in the museum’s fossil preparation lab. Fossils from the excavation are also on display at the Quarry Exhibit Hall and the Utah Field House of Natural History State Park Museum.” After the fossils were removed, the parking lot and road improvement projects were completed.

The Quarry Exhibit Hall—the most popular visitor attraction in Dinosaur National Monument—houses the “Wall of Bones,” with around 1,500 dinosaur fossils still encased in rock.

Where else has Diplodocus remains been found?

On September 15, 2026, Spain’s Fundación Dinópolis announced research identifying Diplodocus remains from El Castellar in Teruel. The remains included 14 tail vertebrae and several chevrons—bones beneath the tail vertebrae—from sediments dating back around 150 million years. Researchers called it the first evidence of the genus outside North America.

Alberto Cobos, managing director of the Dinópolis Foundation and a co-author of the study, said, in remarks translated from Spanish:

“The Diplodocus from El Castellar was approximately 25 meters long, making it another of the great giant sauropods of the Jurassic period in Spain, along with other sauropod dinosaurs from Teruel with very different characteristics from diplodocids, such as Turiasaurus and Losillasaurus, among others.

“The fossils of all these dinosaurs, including those of the new Diplodocus, which make Teruel a reference point for understanding this great diversity, are currently on display in the dinosaur hall of the Aragonese Museum of Paleontology at Dinópolis in Teruel.”