The story of human evolution in Southeast Asia is clearer thanks to a new study initiated in 2004 by the late Mike Morwood, Professor of Archaeology at the University of Wollongong.
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The research, published in Nature, dates fossils found in Indonesia as being between 117-108,000 years old.
The fossils, 12 Homo erectus skull caps and two lower leg bones, were found at Ngandong on the Solo River in Central Java by Dutch geologists Oppenoorth and ter Haar, excavated in a terrace of the ancient river, now 20 metres above the present-day river.
The new dating has established the true age of Homo erectus fossils discovered there in 1931-33, showing them to be the last known occurrence world-wide of the species, an ancestor of modern humans.
Previous attempts to date the site returned very young ages (53-27,0000 years) and much older ages (143-500,000 years).
The international team that conducted the research was led by Indonesia's Institute of Technology, Australia's Macquarie University, and University of Iowa, USA - and included UOW researchers.
The findings have wide implications for the story of human evolution and help to establish the time in which Homo erectus occupied Central Java, who they interacted with, and - potentially - why they went extinct.
The study's joint lead author, Macquarie University Associate Professor Kira Westaway, said the research team applied a regional approach to dating the site and interpreted the evidence within the wider landscape of Central Java.
"Previous studies fixated on the evidence itself, so instead we viewed the fossils as a piece of a much larger puzzle, and tried to understand how they fitted into the wider valley and region," Prof Westaway said.
As well as using several different methods to date the site at Ngandong, the researchers carried out excavations at other sites nearby.
The new study was initiated in 2004 by Prof Morwood, best known for discovering the hominin species Homo floresiensis (also known as "hobbits") at Liang Bua on the Indonesian island of Flores, who took the opportunity to re-investigate the Ngandong site during a period when he was unable to work at Liang Bua.
A team including Prof Morwood, Prof Westaway and Dr Gerrit van den Bergh from UOW's Centre for Archaeological Science, excavated at a site called Sembungan, also on the Solo River, five kilometres south of Ngandong.
"We were hoping to find more hominin fossils, of course. We didn't, but we found stone artefacts, which they don't have at Ngandong,," Dr van den Bergh said.
"This is the most rigorous dating attempt thus far for the last occurrence of Homo erectus.
"Other studies have placed modern humans in China 120,000 years ago, so we are closer and closer to finding an overlap between Homo erectus and modern humans in Southeast Asia."