“Resurrected”: North America’s Most Complete Mosasaur Fossil Reveals the Ultimate Ocean Super-Predator

In a discovery described as “paleontology’s resurrection moment,” scientists have unveiled the most complete mosasaur skeleton ever found in North America — a near-perfect 13-metre (43-foot) specimen of Mosasaurus missouriensis that preserves every major bone, dozens of teeth, and even traces of stomach contents, offering an unprecedented look at the apex predator that ruled the Late Cretaceous seas.

Excavated in 2023–2025 from the Pierre Shale of South Dakota by a Black Hills Insтιтute team led by Dr. Peter Larson, the fossil was recovered in 202 articulated blocks after three years of painstaking work. CT scans reveal a mᴀssive skull with 60+ serrated teeth, powerful jaw muscles capable of a 20,000-newton bite, and a flexible tail that propelled it through water at speeds up to 30 km/h.

Stomach contents include fish bones, shark teeth, and fragments of a juvenile plesiosaur — direct evidence this 70-million-year-old giant was an opportunistic super-predator that dominated the Western Interior Seaway. Its four paddle-like limbs and streamlined body confirm it was a fully marine hunter, not a coastal ambush predator.

Larson called the specimen “the closest thing we have to bringing a living mosasaur back to life.” The find resolves long-standing debates about mosasaur growth rates and diet, showing these reptiles reached full size in under 15 years and fed at the top of a complex marine food web.

Now on permanent display at the Museum of the Rockies after a major restoration, the skeleton is already drawing record crowds. This “resurrected” mosasaur proves North America’s ancient oceans hosted predators every bit as formidable as T. rex — and far more complete in the fossil record than anyone dared hope.