A scientist from the Netherlands was about to quit searching when he came upon a skull fragment.
A recent discovery stemming from a massive construction project reveals evidence of a previously unknown group of Homo erectus that lived off the coast of Java, Indonesia, 140,000 years ago. Skull fragments and other fossil remains emerged from among more than 6,000 animal fossils found in some 177 million cubic feet of sand and sandstones that were dredged up in 2014-15 during excavation for a construction project that is creating an artificial island.
Leiden archaeologist Harold Berghuis, in his capacity as a geotechnical consultant for the port of Surabaya, spent weeks on his hands and knees, searching amid the dredged-up sand, during which he "dreamed" of finding hominin fossils, reports Live Science.
It was on his last planned day of searching that something turned up, he said.
"It was already getting dark and I sat down to enjoy [the] sunset," Berghuis said. "And then, right beside me, lay this fossil that reminded me so much of the only Dutch Neanderthal. This is a well-known fossil in my country, dredged from the North Sea." It once belonged to an adult or adolescent Homo erectus, he said. Berghuis is the lead author in a series of papers revealing the discoveries, published in the journal Quaternary Environments and Humans.
This is the first time such fossils have been uncovered from the seabed between the Indonesian islands, known as Sundaland, an expansive lowland during the last Ice Age.
"This makes our discoveries truly unique," Berghuis tells Science X.
Homo erectus is a key ancestor of modern humans. Emerging at least two million years ago, they were the first to develop human-like proportions and the first to migrate out of Africa, eventually arriving in Southeast Asia, Live Science explained. Berghuis told the publication that by 350,000 years ago, Homo erectus was being replaced on the Asian mainland by the little-known Denisovans and by Neanderthals, and went extinct by about 108,000 years ago. Homo erectus fossils had previously been located on the island of Java, including at well-known sites like Trinil, Sangiran and Ngandong.
Experts previously believed that Homo erectus were isolated on Java, but the new finds reveal that these people spread out over the surrounding lowlands during times when sea levels were lower, and the current islands were mountain ranges.
The bones reveal key information on how Javanese Homo erectus sustained themselves while likely spreading along the region's major rivers. "Here they had water, shellfish, fish, edible plants, seeds and fruit all year round," Berghuis told Science X. "We already knew that Homo erectus collected river shells. Among our new finds are cut marks on the bones of water turtles and large numbers of broken bovid bones, which point to hunting and consumption of bone marrow."
They hunted strong bovids, a class that includes cattle, bison, buffalo, and antelopes, unlike earlier Homo erectus on Java, though it was known that more modern human species on the Asian mainland did so, Berghuis told Science X, adding that "Homo erectus may have copied this practice from these populations. This suggests there may have been contact between these hominin groups, or even genetic exchange."
Working with Berghuis was a team of researchers from Leiden University, the Netherlands, and a global team of specialists hailing from Indonesia as well as Australia, Germany and Japan.
The fossils are on view at the Geological Museum in Bandlung, Indonesia, which is planning a special exhibition.