By Matt Walker
Editor, Earth News
An artist's impression of Velociraptor scavenging Protoceratops
A predatory Velociraptor has been caught in the act of eating another larger plant-eating dinosaur.
Palaeontologists have uncovered fossil fragments of Velociraptor teeth alongside scarred bones of the large horned herbivore Protoceratops.
The teeth of the predator match marks on the herbivore's bones, suggesting Velociraptor scavenged its carcass.
The discovery is further evidence that predatory dinosaurs both hunted and scavenged their plant-eating relatives.
The find also helps validate another famous fossil discovery unearthed in 1971.
Known as the "fighting dinosaurs", that fossil shows a Velociraptor and Protoceratops apparently locked in combat, with both dinosaurs having died at the same time.
Evidence of feeding by theropod dinosaurs, such as Velociraptor or Tyrannosaurus rex, are scarce in the fossil record and the fighting dinosaurs is the most dramatic example known potentially illustrating such behaviour.
Palaeontologists continue to debate the fossil and many still consider it possible that the two animals killed each other - the Velociraptor's raptor-like claw is preserved lodged in the throat region of the much larger Protoceratops, which appears at the same time to be biting down on the predatory dinosaur's right arm.
However, it is also possible that Velociraptor did not regularly eat Protoceratops.
Bite marks on Protoceratops bone
Instead, the fighting dinosaurs could represent a chance encounter between the two species that escalated into a fight.
However, the new fossil discovery, published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology, suggests that is less likely.
It provides further evidence that Velociraptor did regularly eat Protoceratops, either by scavenging those that had already died or by actively hunting them.
Dr David Hone of the Chinese Academy of Sciences in Beijing made the new discovery in Upper Cretaceous deposits at Bayan Mandahu, in Inner Mongolia, China.
Colleague Dr Jonah Choiniere originally found a mass of badly eroded Protoceratops bones. Among them lay two Velociraptor-like teeth.
Velociraptor teeth match the bite marks
Together with Dr Hone and colleagues Dr Corwin Sullivan and Dr Mike Pittman, Dr Choiniere analysed the fossils for bite marks.
The team found the Protoceratops bones were scarred in this way, and the bite marks matched the teeth found alongside.
The Velociraptor found at the site likely scavenged this particular Protoceratops, rather than hunted it.
"The marks were on and around bits of the jaw," Dr Hone told the BBC.
"Protoceratops probably weighed many times what a Velociraptor did, with lots of muscle to eat. Why scrape away at the jaws, where there's obviously not much muscle, so heavily that you scratch the bone and lose teeth unless there was not much else there.
"In short, this looks like scavenging as the animal would be feeding on the haunches and guts first, not the cheeks.
"The fighting dinosaurs suggests predation. Combine the two and we have good evidence for both behaviours," says Dr Hone.
"Animals like Velociraptor were probably feeding on animals like Protoceratops regularly, probably including both predation and scavenging."
That is in line with the behaviour of many modern predators, as almost all living carnivores such as lions and jackals do both.
"It's a question of degree," says Dr Hone. "Lions mostly predate, jackals mostly scavenge."
In that regard, the new fossil find confirms what many researchers have long suspected about how predatory dinosaurs such as Velociraptor interacted with plant-eating dinosaurs.
"Even the most dedicated predator won't turn down a free meal if they chance across a dead animal with a few bits of meat still attached, and this looks like the case here," says Dr Hone.