The entrance to Lida Ajer, a cave in the Sumatran highlands of Indonesia. Researchers say teeth found at the cave belong to anatomically modern humans and are up to 73,000 years ago. (Credit Julien Louys) The conventional timeline of human evolution and migration continues to crumble in the face of new research. The latest finding puts anatomically modern humans deep in Indonesia up to 73,000 years ago — tens of thousands of years before once thought possible. The old school timeline, still widely taught, went something like this: Homo sapiens evolved into a distinct species from earlier hominins about 200,000 years ago in Africa and became anatomically modern humans (AMHs) about 100,000 years ago. Then, around 50,000 years ago, the AMHs headed out of Africa and spread through Eurasia, interbreeding with (and eventually replacing) Neanderthals and Denisovans. Easy. Tidy. Except for all that pesky confounding evidence that continues to emerge. Just in the last year, for example, both paleoanthropological and paleogenetic discoveries have pushed back the start date for Homo sapiens, in some cases by hundreds of thousands of years. And in July, a compelling study in Nature found evidence of humans in northern Australia by about 65,000 years ago (that's about 15,000 years before AMHs supposedly left Africa, if you're keeping score). The researchers dated more than 10,000 artifacts from Madjedbebe, a site not far from the modern coastal city of Darwin. Today, a separate team announced that they have analyzed teeth from Lida Ajer cave, a site in the highlands of Sumatra in Indonesia, and found them to be from AMHs — and they're 63,000 to 73,000 years old.