Dinosaur bones were found in a suburb in Thornton this past August. The seeming bones of a Triceratops turned out to be of a much rarer dinosaur. In August a Torosaurus, the Triceratops’ close cousin was found on a construction site. The Torosaurus is a massive three-horned beast weighing over 8000 pounds and is one of the rarest dinosaurs on the planet. The Denver Museum of Nature and Science will be adding this new addition to their dinosaur collection.

The museum announced on Tuesday that the fossils surfaced on Aug. 28 at the construction site of a future police and fire station. An engineer made an immediate stop in digging when a soil examination revealed something inconsistent with the area’s landscape. A lower jaw, brow and shoulder bones and, even a stray T. rex tooth were found after careful examination, The Denver Post reported. More of the skeleton is now identified, the museum said, making the torosaurus.

The number of triceratops specimens collected from West America likely exceeds 2,000, there are only seven partial skulls of torosaurus known. “Not only is the fossil more complete and better preserved than I imagined, but it has also revealed itself to be something extremely rare,” says Joe Sertich, the museum’s dinosaur curator. He also said in a statement. “The Thornton beast is by far the most complete, and best-preserved, ever found.”

The dinosaur is still under construction at the Denver Museum of Nature and Science but will hopefully be on display soon. You can go and observe scientists as they study and prepare the fossils. If you go to the museum you can see the other dinosaurs and ask questions about the Torosaurus. The museum is open every day from 9 am-5 pm and on Fridays from 9 am-9 pm.