Startling genetic diversity indicates that ancient Papuans didn't even mix with each other: The ancestors of the Papuan New Guinean peoples arrived 50,000+ years ago, scattered into highland and lowland areas, and evidently kept to themselves since then, going by genetic and linguistic evidence

The latest twist in the history of humankind is that after ancestral Homo sapiens settled Papua New Guinea, which seems to have been around 50,000 to 70,000 years ago, they not only didn't budge. They not only didn't mix with the peoples around them, if any. They didn't even mix with each other, going by the startling degree of genetic and linguistic diversity found between groups of Papuans. In fact, the original occupants of both Papua New Guinea and, later, Australia, seem to have been a very sedentary bunch. The aborigines' forefathers reached Australia at least 50,000 years ago, scattered along the coastline for about 1,500 to 2,000 years and then, having struck roots wherever they struck roots, they didn't budge for the next 50,000 years. An unrelated study in 2016 postulated that aboriginal Australians and Papuans diverged from Eurasians anywhere from 70,000 to 50,000 years ago. This postulation is bolstered by the new study, which indicates that the Papuans would remain genetically independent from Europe and Asia for most of the last 50,000 years.