Scuba-diving archaeologists have unearthed artefacts from an ancient butchering site that seem to settle a debate about when humans spread across the Americas. Working in the murk of a river in Florida, the team found stone tools dating back 14,550 years that could have been used to carve up ancient elephant-like beasts called mastodons, whose remains have been recovered from the same site. The findings, published today in Science Advances, add to ever-growing evidence that humans were living in much of the Americas well before the cultural group known as Clovis were present about 13,000 years ago. The alternative theory — that the Clovis group were the first Americans — has been increasingly disputed.
