Some periods of human prehistory lack a substantial fossil record in key geographic locations, making it difficult to confirm genetic evidence of modern human migrations. One such crucial period was when the earliest modern humans migrated from East Africa after having originated there 150,000 years ago. Genetic analysis shows that populations of our direct ancestors left this area between 65,000 and 25,000 years ago, spreading elsewhere in Africa, to Europe, and eventually, around the world. Although plenty of fossils have been discovered in this time period in Europe and North Africa, nothing had turned up in Africa south of the Sahara Desert.

But just such a specimen turned out to be already available. Using a new dating technique called luminescence, a team led by Frederick Grine of Stony Brook University dated for the first time a skull found in 1952 in a dry riverbed in South Africa. The scientists learned the skull was 36,000 years old, filling this gap in the African fossil record. Learn what this fossil suggests about the first modern human migrations in this Human Bulletin.