If you were wandering around Earth's floodplains 415 million years ago, you wouldn't have come across any other mammals – but you would have had to be wary of a giant scorpion measuring more than a meter (3.3 feet) in length. After an extensive new fossil study , researchers in the UK have confirmed the identity of Praearcturus gigas , which may be the largest known scorpion in history. Fossils of the arthropod were first discovered in 1870 in the UK, but there's been a debate ever since about