Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more . Summary Stone tools discovered in southwest China could challenge what's known about human origins during the Stone Age. The tools, found at Longtan site, were crafted in Neanderthal-associated Quina style, unprecedented in East Asia. Neanderthals might have migrated to China or other ancient humans developed similar tools, researchers suggest. The