Recent archaeological discoveries in Java provided new insights into the migrations and habitats of Homo erectus, challenging long-held assumptions about this ancient human species. The findings, published in the journal Quaternary Environments and Humans, include two newly discovered skull fragments belonging to Homo erectus, offering a unique perspective on how and where these early humans lived around 140,000 years ago.
According to Discover Magazine, the fossil remains were found after a marine sand extraction project in the Madura Strait, part of a land reclamation project conducted between 2014 and 2015. The Madura Strait, now submerged under the ocean, was once part of the extensive Sundaland landmass—a vast lowland area that connected the Asian continent with present-day Indonesia during periods of lower sea levels.
"These fossils come from a drowned river valley, which filled up over time with river sand," said Harold Berghuis, an archaeologist at Leiden University and co-author of the study, according to Discover Magazine. "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."
The findings indicate that Homo erectus did not live in isolation on Java, as previously believed. Research conducted by scientists from Leiden University and international experts reveals that this species spread into the surrounding lowlands of Sundaland during periods of lower sea levels in the Pleistocene epoch, supporting the idea of a prehistoric land bridge that allowed Homo erectus to disperse throughout the region.
"Here they had water, shellfish, fish, edible plants, seeds, and fruits all year round," said Berghuis, noting the favorable living conditions in Sundaland. Evidence suggests that Homo erectus traveled along river systems such as the Brantas and Solo Rivers, finding abundant resources along the way.
Among the discoveries are also traces indicating hunting and food processing. Researchers found cut marks on the bones of aquatic turtles and a large number of broken bovid bones, indicating that Homo erectus hunted and consumed bone marrow. This practice was previously unknown among Javanese populations of Homo erectus but is documented among their continental relatives.
"We did not find this in previous Homo erectus populations in Java, but we know it from more modern human species on the Asian mainland," noted Berghuis. "Homo erectus may have imitated this practice from those populations."
The study suggests that Javanese Homo erectus may have had contacts with other groups of hominins, possibly leading to cultural and genetic exchanges. This challenges the notion that they lived in isolation and points to a more complex and interconnected existence.
Around 140,000 years ago, Sundaland resembled modern African savannas—dry plains with forests along rivers, inhabited by elephants, rhinoceroses, and other large animals. Fossil remains of extinct species, including Asian hippopotamuses, Komodo dragons, and river sharks, were also discovered during the sand extraction project.
Previously, fossil remains of Homo erectus had been found on the island of Java at sites such as Trinil, Sangiran, and Ngandong. However, no fossils had been found in underwater regions like the Madura Strait. The discovery marks the first finding of fossils on the seabed in this part of the world, providing evidence of vertebrate life on the ancient Sundaland landmass.
The research was conducted by scientists from Leiden University in collaboration with experts from Indonesia, Australia, Germany, and Japan. The team analyzed over 6,000 fossilized remains, including fragments of Homo erectus skulls and bones belonging to 36 species of vertebrates, uncovered during the marine sand extraction.
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