A newly discovered raptor shows that these dinosaurs stalked America’s Southwest right up to the bitter end.
The raptor was discovered from a 67-million-year-old fossil, dating it to within a million years of the cataclysmic event that killed off all non-flying dinosaurs.
The dinosaur has been named Dineobellator notohesperus, which means ‘Navajo warrior from the Southwest’, in honour of the people who live in the region where this dinosaur once roamed.
It belongs to a family of dinosaurs known as the dromaeosaurids, the most famous of which is Velociraptor – that’s why these dinosaurs are commonly known as ‘raptors’.
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Dineobellator was a lightly-built, meat-eating predator, about two metres in length. Features on the animal’s forelimbs suggest that it boasted unusually strong arms and claws – handy for holding onto prey such as birds and lizards, or grappling with other dinosaurs.
Its tail was also unusual. Unlike other raptors, Dineobellator could move its stiff tail at its base, using it almost like a rudder as it raced across the ground.
“Think of what happens with a cat’s tail as it is running,” said Steven Jasinski, who led the study while completing a PhD at the University of Pennsylvania. “While the tail itself remains straight, it is also whipping around constantly as the animal is changing direction. A stiff tail that is highly mobile at its base allows for increased agility and changes in direction, and potentially aided Dineobellator in pursuing prey, especially in more open habitats.”
And, just like Velociraptor, it looks like Dineobellator sported feathers. Bones from the dinosaur’s forearm had quill knobs – small bumps on the surface where feathers would be attached by ligaments
“As we find evidence of more members possessing feathers, we believe it is likely that all the dromaeosaurids had feathers,” said Jasinski.
Reader Q&A: Why didn’t dinosaurs evolve to be more intelligent?
Asked by: Steve Barron, Northumberland
They did! Dinosaurs evolved into modern birds and some of them are extremely intelligent. In Japan, there are crows that have learnt to use the traffic to crack the shells of nuts that they drop – and they will wait for the lights to turn red, so they can safely retrieve them.
One reason that birds still aren’t as intelligent as humans is that a heavy, energy-hungry brain doesn’t mix well with birds’ main adaptive advantage – flying. It’s important to realise that intelligence isn’t the goal of evolution, nor is it always the best adaptation to the environment. The enormous sauropod dinosaurs lasted on the planet for 100 million years, despite their tiny brains. We’ve had ‘intelligence’ for just a few million years, so it’s too early to say whether it is a better strategy.