Huge dinosaur footprints belonged to one of the largest raptors ever

Five enormous dinosaur footprints found in south-east China were made by one of the largest raptors of all time. The predator probably measured 5 metres from snout to tail, roughly half the length of a school bus. And it would have attacked its prey using a pair of enormous “killing claws”, one on each foot.

Most raptors – technically known as deinonychosaurs – were small. Velociraptor, for instance, was roughly the same size as a turkey. But a handful of these dinosaurs grew larger, including Utahraptor and Dakotaraptor, which both reached lengths of roughly 5 or 6 metres.

Scott Persons at the College of Charleston in South Carolina and his colleagues have now added another giant raptor to the list. They named it Fujianipus, and they say it lived in East Asia about 96 million years ago.

We still know relatively little about Fujianipus because Persons and his colleagues have yet to find any parts of its skeleton. Instead, they discovered a handful of its 36-centimetre-long footprints. “Preservation conditions were right for footprints but not so great for bones,” he says. But they are sure the footprints belong to a raptor because each one carries the imprint of just two toes. This matches the foot anatomy of the raptors, which had three toes but held one off the ground to protect the large claw at its tip from wear and tear.

Persons says Fujianipus shows that the raptors had the potential to grow even larger and compete against the biggest predatory dinosaurs on the landscape at that time – the allosauroids, some of which measured 10 metres or more in length. He adds that the raptors may have had one key advantage over these rivals: “They were fast.”

Ultimately, however, the raptors grew little larger than Fujianipus. Persons says that might be because a third group of predatory dinosaurs was beginning to rise to dominance: the tyrannosauroids. “Competing against the tyrannosauroids was much harder because many of them were fast too,” he says.