Meet “Cliff”: A Rare Allosaurus jimmadseni Arrives at the Museum of Ancient Life 

The story of Cliff begins in the spring of 2021 during a fossil prospecting expedition near the small town of Hyattville, Wyoming. While surveying a new area near a 200-foot cliff edge, researchers began noticing small bone fragments eroding from the surface—an exciting sign of something much bigger beneath the ground. 

Careful excavation revealed the remains of a powerful predator: an Allosaurus jimmadseni, a species formally identified as distinct only a year earlier, in 2020. Discoveries like this are rare and scientifically significant, helping paleontologists better understand the diversity of dinosaurs that lived during the Jurassic Period. 

Thanksgiving Point is proud to welcome this extraordinary fossil to the Mountain America Museum of Ancient Life. The arrival of Allosaurus jimmadseni adds an important new chapter to the museum’s world-class dinosaur collection and gives guests a chance to learn about cutting-edge paleontology. 

Unlike the more familiar Allosaurus fragilis, this species is helping scientists rethink long-held assumptions about Jurassic predators and the ecosystems they dominated. 

See this rare apex predator up close – plan your visit to the Museum of Ancient Life today!

1. It’sa Recently Recognized Species 

Allosaurus jimmadseni was formally identified as its own species in 2020, making it one of the newest additions to the Allosaurus family tree. This discovery highlights how much there is still to learn about dinosaurs. 

2. A True Apex Predator

Like other allosaurs, this dinosaur sat at the top of the food chain. With sharp teeth, powerful jaws, and strong claws, it was perfectly adapted for hunting large prey during the Jurassic Period. 

3. It Lived Alongside Other Giant Dinosaurs

Allosaurus jimmadseni shared its environment with massive herbivores such as sauropods and stegosaurs. Studying this species helps scientists better understand predator-prey relationships in Jurassic ecosystems. 

4. “Cliff” Helps Rewrite Jurassic History

Because this species was only recently identified, fossils like Cliff are helping paleontologists re-evaluate fossils once thought to belong to other Allosaurus species—reshaping what we know about dinosaur diversity.