A final outpost on the Solo River
In the 1930s, Dutch surveyors excavating a river terrace near Ngandong village in Central Java made a remarkable find. Buried in sediment 20 meters above the modern Solo River were twelve partial skulls (calvaria) and two lower leg bones (tibiae) of Homo erectus. This species of archaic human first arose in Africa nearly 2 million years ago and had spread across Asia, but was thought to have vanished by 400,000 years ago. The Ngandong fossils, however, appeared much younger, representing the most evolutionarily significant members of their species ever found.
For decades, the precise age of the Ngandong remains was a subject of intense debate, with estimates ranging from 500,000 to just 27,000 years old. A definitive answer came from a 2019 study published in Nature. An international team of scientists re-located the original bone bed using the Dutch surveyors' notes. They used several modern dating techniques, not on the hominin fossils themselves, but on the surrounding river sediments and associated animal fossils. The project involved 52 new age estimates from methods including Uranium-series and electron-spin resonance dating, establishing the age for the site. The results showed the Homo erectus fossils at Ngandong are between 117,000 and 108,000 years old. This confirms Ngandong as the last known appearance of Homo erectus anywhere in the world.