In August, some bones were dug up in a construction site in Thornton, and the Denver Museum of Nature and Science determined it was a triceratops fossil.

That's the end of that story, right? Well, not exactly. Lo and behold, it's actually the rarer torosaurus fossil.

Denver's 'Tiny' Fossil Only Related To Triceratops

When paleontologist and curator of dinosaurs at the Denver Museum of Nature and Science Dr. Joseph Sertich first got ahold of the fossil found in Thornton and nicknamed "Tiny," he thought it was the bones of a triceratops.

As it turns out, it was the bones of the torosaurus. That's the conclusion he arrived to after examining them more closely, so what gave it away? The pieces of frill and the shield on the skull.

Thinking it was the fossil of the triceratops from the get-go is neither right nor wrong. For starters, the torosaurus is its cousin, but more importantly, the discoveries of triceratops in the area are relatively greater.

"While the number of good Triceratops specimens collected from the American West likely exceeds 2,000 individuals, there are only about seven partial skulls of Torosaurus known. The Thornton beast is by far the most complete, and best preserved, ever found," Dr. Sertich said.

Triceratops vs. Torosaurus

The deciding factor that distinguishes the torosaurus from its cousin is the frill in which it's longer and has two large holes. In the case of the triceratops, it's a "solid frill."

At the time of the discovery, Dr. Sertich already suspected that the fossil was of the torosaurus, but he didn't want to jump to conclusions.

"It's hot, there's a lot of dirt, we don't want to clean them too much. So we really need to get them back to the lab. We needed these few months to really see what this frill looked like," he said.

An Important Find

Needless to say, unearthing fossils that give clues to how things were like in prehistoric times is important, but this case is a little bit special.

The Denver Museum of Nature and Science describes the torosaurus bones as a "complete Cretaceous period fossil discovered in Colorado," estimating that 95 percent of the skull and 20 percent of the skeleton at the minimum has been identified.

Now it's safe to expect that more info will turn up soon enough since the team of scientists are still hard at work in cleaning and examining the fossil, after all. But it's probably a stretch to think it'll be reidentified as another dinosaur again.