Ankylosaurus emerged about 65m years ago, two million years after the arrival of the dinosaurs, researchers say
Fossils reveal a new dinosaur species that was the size of dogs
Ankylosaurus, a new dinosaur species, has been found after scientists found it hiding in plain sight in Argentina.
The meat-eating dinosaur, which roamed Argentina 65m years ago, was bigger than had been previously thought. Initially thought to be approximately 80m long, it turned out to be a whopping 70m to 80m (264m to 270m) long.
In some of the oldest bones found in the Andes, scientists found ankylosaurus bones nearly as big as living dogs.
The dinosaur can be seen in the latest edition of the journal Science.
One theory for how the huge new dinosaur, which roamed alongside the dinosaurs 65m years ago, came to be has to do with climate change.
At the time, temperatures were around minus 4C (27F) in the northern hemisphere, with a chillier, dry South America. Perhaps this climate change made dinosaurs more vulnerable to biting insects, especially that associated with moths, and the evolutionary move to smaller and more robust animals such as this would be likely.