This Labrador-sized dinosaur is shaking up what we thought we knew about Jurassic life.
A dinosaur the size of your neighbor’s Labrador just rewrote part of prehistoric history. Called Enigmacursor mollyborthwickae, this little runner lived in what’s now Colorado about 150 million years ago, right alongside celebrities like Stegosaurus and Diplodocus. Its discovery proves Jurassic ecosystems weren’t just about the giants. There were smaller players filling hidden roles, zipping through undergrowth while massive long-necked dinosaurs and plated tanks lumbered above. This isn’t just another fossil story—it’s a window into the parts of ancient life we rarely see.
1. Its size made it stand out in a land of giants.
Picture a Labrador-sized dinosaur weaving around the feet of animals the size of buses. According to Royal Society Open Science, Enigmacursor’s bones show it was small compared to its neighbors, which hints at it living life on the edges of the ecosystem. That smaller frame likely allowed it to survive where heavyweights couldn’t go, nibbling on vegetation or maybe even insects while staying out of trouble. Its scale shows not all dinosaurs were massive, bone-crunching beasts—some thrived precisely because they were built small and quick.
2. The tail was half its body, and that’s not for style points.
A tail making up nearly half its body screams balance and speed. Researchers reported to CNN that this dinosaur’s design suggests it was agile, maybe darting between vegetation or outrunning predators with quick bursts of speed. That kind of tail also hints it had great maneuverability, like an ancient greyhound made of scales and bone. If you picture it weaving through dense Jurassic plants, using that long tail like a steering rudder, you’re probably not far off. Small doesn’t mean weak—it often means efficient.
3. Even missing pieces couldn’t hide its unique story.
Enigmacursor’s skull and parts of its spine are still missing, but paleontologists were able to identify unique features that earned it its own name. The fossil was collected from the Morrison Formation during 2021 and 2022, then analyzed for distinctive traits. Despite the gaps, researchers could tell this wasn’t just another known species. That’s impressive because, according to Royal Society Open Science, small dinosaur bones often get overlooked or mistaken for juveniles of bigger species. This one stood out enough to earn its own chapter in dinosaur history.
4. It shared space with some of the most famous dinosaurs ever.
Imagine living in the same world as Stegosaurus and Diplodocus but being a fraction of their size. That was Enigmacursor’s reality. These famous plant-eaters towered above the landscape, but small dinosaurs like Enigmacursor likely filled entirely different ecological roles, scooting into places where the giants couldn’t reach. That means Jurassic ecosystems were layered, full of tiny specialists weaving between the giant celebrities. This isn’t just a cool footnote—it’s a clue that ancient life was more dynamic and diverse than we often picture.
5. Its name honors someone who helped make discoveries like this possible.
The second half of its name, mollyborthwickae, honors Molly Borthwick, who supported paleontological research. That’s a tradition in science—naming species after people who make discoveries possible through funding or support. It’s a reminder that groundbreaking finds don’t happen in isolation. Behind every fossil discovery, there’s often someone who believed in the work enough to invest time or money. Without that kind of backing, fossils like this might have stayed hidden underground for another century.
6. The Morrison Formation just keeps delivering surprises.
For over a hundred years, the Morrison Formation has been a fossil goldmine. It’s given us some of the most iconic dinosaurs ever, but Enigmacursor proves there are still discoveries waiting under familiar ground. It shows paleontology isn’t slowing down just because we’ve been digging in the same place for decades. Every new species adds another puzzle piece, showing how diverse these ecosystems really were. It’s like every dig brings a new plot twist to a story we thought we already knew.
7. This wasn’t a clunky plant-muncher—it was built for movement.
Even without a skull, its limb proportions and long tail suggest speed and agility were its superpowers. This dinosaur wasn’t about raw power. It was about weaving through shrubs, avoiding predators, and taking advantage of food sources that bulky dinosaurs couldn’t reach. That kind of specialization makes you think of how rabbits or small deer thrive alongside massive animals today. It’s a different survival strategy, one built around speed and awareness rather than intimidation.
8. The discovery proves there’s more waiting underground.
If a well-studied formation like the Morrison can still surprise scientists with something brand new, what else is hiding underfoot? Enigmacursor is a reminder that small, delicate fossils often go unnoticed or uncollected, meaning our picture of ancient ecosystems is still incomplete. Each new species like this one fills in blanks we didn’t even know were there. And that’s why paleontologists keep digging—it’s not just about chasing big skeletons but also about finding the hidden players that made prehistoric life so complex.