What kind of predator was it?

Megaraptors were two-legged carnivores related to tyrannosaurs, but they hunted differently. Instead of relying on crushing jaws, they likely used powerful arms and large curved claws to attack prey and defend themselves.

By megaraptor standards, I. amberina was small. The researchers estimate it measured 10 to 13 feet (3 to 4 meters) long, stood roughly 5 feet (1.5 m) tall, and weighed 440 to 660 pounds (200 to 300 kilograms). Compare that with Maip macrothorax from Argentina, which may have reached 33 feet (10 m) and weighed as much as an elephant.

Small doesn't mean safe, though. "It was not the apex predator of its time, but for humans this dinosaur would have been more dangerous than a T. rex," Morrison said. "We would have been perfectly sized prey, about a third of their body weight. They definitely would have chased us."

Here's what the fossil doesn't show. No arms. No claws. The researchers infer from its closest relative that its claws may have measured 4 to 8 inches (10 to 20 cm) long, and they suggest it may have been feathered — but the specimen itself can't confirm either claim. Read those numbers as educated inference, not observation.

What does this change for dinosaur migration?

Scientists have long suspected megaraptors originated in Asia, spread outward, and eventually dominated the southern supercontinent Gondwana — the landmass that included present-day Africa, South America and Antarctica. The problem: no European fossils. Without them, the migration route stayed a hypothesis.

The study's evolutionary models suggest I. amberina descended from Asian megaraptors that dispersed into Europe around 130 million years ago, then moved through what is now Africa toward Gondwana via temporary land connections across the shallow Tethys Ocean.

"This new species is the first proof we have that megaraptorans were also present in Europe and that they reached Gondwana this way rather than island-hopping further south," study co-author Charlie Scherer, a doctoral student at UCL Earth Sciences, said in the statement.

Plenty remains unanswered. The researchers cannot yet pin down the exact route these animals took over millions of years. Nor can they explain why megaraptors vanished from northern regions, though climate shifts or competition with other predators may have played a role. One skull fills a gap; it doesn't close the file.

The quieter lesson may be the one co-author Paul Barrett of the Natural History Museum drew: "Work like this shows the exceptional value of working with historical museum collections where there are still many discoveries to be made."

Sometimes the next discovery isn't in the ground. It's in the drawer.