A Megaraptor emerges from the footprint fossils

Thanks to their reign of terror in “Jurassic Park,” Velociraptors are infamous prehistoric predators.

The scythe-like killing machines familiar to viewers, however, are a far cry from their scientific counterparts – and not just because the fictional ones don’t have feathers. In real life, Velociraptors reached the size of a Labrador Retriever and were much smaller than the human-sized hunters depicted in the film series.

However, some birds of prey have reached impressive sizes. And a team of paleontologists said they may have identified a new megaraptor based on a set of fossil footprints found in China. In a paper published this week in the journal iScience, researchers estimated that the tracks were left by a dinosaur that would be among the largest birds of prey known to science.

The raptor footprints are part of a larger dinosaur trail discovered in southeast China in 2020. During the Late Cretaceous period, about 90 million years ago, the area was a muddy river plain that was home to all kinds of dinosaurs, including long-necked sauropods and ducks. large-billed herbivores. As these dinosaur inhabitants walked, they left muddy footprints, some of which have been preserved for tens of millions of years.

In Longxiang, about 240 dinosaur tracks were discovered at the site of the rink, which are about the size of a hockey rink. Some footprints are oddly shaped, with preserved footprints featuring only two toes.

“When you see dinosaur footprints with only two toes, you can play the Cinderella slipper game and look for feet that match them,” said Stephen Brusatte, a paleontologist at the University of Edinburgh who was not involved in the new study. “The only dinosaurs that walked on two toes were ‘raptors’ such as the velociraptor and their close relatives.”

The birds of prey left such strange footprints because their inner toes were raised off the ground. This prevented the tip’s oversized, curved claw from dragging on the ground and becoming blunt.

Many of Longxiang’s bituminous tracks appear to have been left by a small dinosaur the size of a velociraptor. But researchers found a set of five tracks more than 13 inches long, making them the largest raptor tracks in the fossil record. Based on the size of the tracks, the dinosaur that left them was about 5 feet tall and 15 feet long, placing it in the vicinity of the largest known raptors, including Utahraptor.

Its distinct footprints inspired paleontologists to name the new raptor Fujianipus (meaning “Fujian foot”) yingliangi. Although finding fossilized bones would help researchers better understand the animal’s appearance, the proportions of its two toes make it likely that Fujianipus was a troodontid, a type of bird-like raptor that inhabited Asia and the North. America during the Cretaceous period.

Birds of prey are often depicted as fast-paced predators. But footprints alone cannot provide insight into how fast Fujianipus moved, according to W. Scott Persons, a paleontologist at the College of Charleston in South Carolina and co-author of the new paper.

According to him, the bird of prey was most likely watching his steps as he crossed the muddy river bed. “When you walk on mud, you move very carefully to avoid slipping,” Dr. Persons said. “It was probably the same for our bird of prey.”

Without fossilized leg bones, researchers cannot estimate Fujianipus’ speed. But members of the troodontid group, to which it probably belonged, were “among the lightest raptors of all”, Dr Persons said, suggesting that Fujianipus was probably a fast predator.

Speed ​​would have come in handy during the Late Cretaceous, a time when ancient lineages of predatory dinosaurs were gradually giving way to emerging groups of carnivores such as raptors and lanky tyrannosaurs.

“During this period, it appears that these two iconic dinosaur groups, the tyrannosaurs and the raptors, were both vying for that crown of medium-sized predators,” Dr. Brusatte said.

While tyrannosaurs continued to grow into behemoths like Tyrannosaurus rex, raptors remained largely small. Giants like Fujianipus and Utahraptor are outliers.

“Raptors experimented with large bodies but, unlike many other groups of carnivorous dinosaurs, they did not stick to them,” Dr Persons said. “It appears that raptors were much better at being small- and medium-sized carnivores than they were at being large.”