The ancient remains of a horned beast uncovered by fossil hunters in Montana belong to the last known dinosaur to walk the Earth and give weight to the theory that the creatures were wiped out by an asteroid.
A brow horn of the creature was found in sedimentary rock deposited shortly before the mass extinction 65.5 million years ago.
The discovery adds to growing evidence that the dinosaurs were wiped out when a comet or asteroid crashed into Earth at the end of the cretaceous.
The animal, most likely an adult triceratops, was not the last dinosaur standing, but the last survivor of their impressive reign to be identified by palaeontologists.
Adult triceratops grew to around 9 metres long and weighed up to 12 tonnes.
Researchers spotted the 45cm horn while hunting for fossils in the Hell Creek Formation, a 100m-thick slab of mudstone in south eastern Montana.