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Homo erectus from the seabed—new archaeological discoveries in Indonesia

Archaeological finds off the coast of Java, Indonesia, provide insight into the world of Homo erectus, 140,000 years ago. Skull fragments and other fossil remains provide a unique picture of how and where these early humans lived, says Leiden archaeologist Harold Berghuis.

During dredging operations in the Madura Strait, archaeologists found the fossilized remains of 36 vertebrate species. This is the first discovery of fossils from the seabed between the Indonesian islands.

This area, called Sundaland, was once a vast lowland. Among the finds are two skull fragments of Homo erectus. Together, the finds provide a unique image of a prehistoric ecosystem and the position of Homo erectus in this ecosystem.

New insights

Fossil remains of Homo erectus have previously been found on the island of Java, the most famous of which are skulls from sites such as Trinil, Sangiran and Ngandong. Until today, researchers thought that Homo erectus had lived for a long time in isolation on Java. The new finds show that the Javanese Homo erectus dispersed over the surrounding lowlands of Sundaland during periods with lower sea levels.

The species probably spread along the major rivers. "Here they had water, shellfish, fish, edible plants, seeds and fruit all year round," says Berghuis. "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."

The new finds show that the Sundaland Homo erectus actively hunted healthy, strong bovids. "We didn't find this in the earlier Homo erectus population on Java, but do know it from more modern human species of the Asian mainland. 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."

A broader view of archaeological research

The site has been studied in detail over the past five years. "Often, only the most attractive material is published in this type of research, such as hominin fossils. We present the results of our studies in four extensive, richly illustrated articles, creating a unique window to the drowned Sundaland of 140,000 years ago," says Berghuis.

The research was carried out by researchers from Leiden University, the Netherlands, in collaboration with a team of specialists from Indonesia, Australia, Germany and Japan. The first of the articles was this week in the journal Quaternary Environments and Humans.

The fossil collection is housed in the Geological Museum in Bandung, Indonesia. The museum is planning an exhibition, and temporary exhibitions may follow at other locations.

What did Sundaland look like?

In prehistoric times, what we know as the Indonesian archipelago was an extensive lowland in periods with lower sea levels, with the current islands as mountain ranges. "We call this area Sundaland," says Berghuis. "Homo erectus could disperse from the Asian mainland to Java." The vast majority of Sundaland is now a shallow sea, and until now, fossils had never been found in this area.

"This makes our discoveries truly unique," says Berghuis. "The fossils come from a drowned river valley, which filled up over time with river sand. We have been able to date the material to approximately 140,000 years ago. That was the penultimate glacial period. Large parts of the northern hemisphere were covered by glaciers, and so much water on Earth was stored in ice caps that the global sea level was 100 meters lower than today."

Elephants, rhinos, hippos, Komodo dragons and river sharks

At that time, Sundaland resembled today's African savannah: a fairly dry grassland with narrow strips of forest along the major rivers and a rich fauna including various species of elephants, bovids, rhinos and crocodiles.

"Most of these species are extinct, whereas others are the ancestors of species that still occur in the region, but whose survival is seriously threatened. The Asian hippo is extinct. Carnivorous Komodo dragons are now restricted to the islands of Komodo and Flores, and river sharks are extremely rare in the major rivers of India and Thailand.

"But all these animals were thriving in ancient Sundaland. This knowledge is hugely important to our understanding of the biodiversity of the whole of Southeast Asia."