Scientists in Chile have discovered the bones of a dinosaur they say used its unusual tail as a deadly weapon.Researchers say the dog-sized creature had a tail weapon unlike those seen on any other animal.The tail had a series of "blades" on each side that could be used to cut its enemies.At first, the scientists thought the plant-eating dinosaur might have belonged to a similar species called stegosaurus.But after studying pieces of skull and examining DNA, the scientists decided the dinosaur must be from a new species.The researchers named the dinosaur stegouros because of its similarities to stegosaurus.The find is described in a study recently published in Nature.Alex Vargas was the lead writer of the study.He told The Associated Press that the animal's blade-like tail could be used as a cutting weapon similar to those used by Aztec warriors.