About 40,000 years ago, when modern seafarers ventured to Java, they discovered a land covered in rainforests. It’s full of life, but they’re not the first humans to call the island home. Their distant homo erectus had been to Java when the land bridge connected to the mainland, where they lived for about 1.5 million years.
According to a new study, the last time these people appeared on the island was about 100,000 years ago. At that time, they were already extinct in other parts of the world. This study sets a reliable age for previously discovered Homo erectus fossils and suggests that orthoral DNA traces may continue to exist in modern Southeast Asian populations. This is due to the complex mix of many humanbeings living in the region.
Patrick Roberts, an archaeologist at the Institute of Human History and Science at the Map Society in Germany who was not involved in the study, said the new fossils also indicate the existence of a very “longevity” human species. “So far, Homo erectus have lived almost three times as long as our species on Earth. There is no doubt that it is successful. He said.
Homo erectus appeared in Africa about 1.9 million years ago. These tool makers have relatively large brains, migrating from Africa to Asia and entering Java by land bridge about 1.6 million years ago. At that time, open woodlands like savannas covered most of the land. Later, sea levels rose and the ancient Javanese were isolated on an island. Meanwhile, in Africa and the Asian continent, Homo suprenos disappeared about 500,000 years ago.
In the 1930s, a team of Dutch explorers excavated a site near the Solo River in Java and unearthed a rare treasure trove of fossils: tens of thousands of animal bones, 12 partial skulls and two leg bones identified as Homo erectus. But the Dutch team was unable to determine the age of the bones. Later scientists also encountered difficulties, and although there were more complex dating methods, they needed to come from material from the same sedimentary layers as fossils, and no one now knew where the initial excavations were carried out.
“These fossils have always been a mystery. “A lot of people have tried to figure out their age, but there’s no way to determine them,” said Russell Ciochon, lead author of the new study and a paleoanthropologist at the University of Iowa. “
Archaeologist at the University of Texas at Austin and co-author of the study, O. Frank Huffman spent five years studying the photographs and notes of these Dutch explorers, and he even met their grandchildren. He and his colleagues concluded that the excavation site in the 1930s was near what is now a sugar cane field, adjacent to a dirt road.
In 2008 and 2010, Ciochon’s team rediscovered the site and found 867 new fossils belonging to deer, bison and an extinct swordtooth elephant. Based on the photos and documents of the original excavations, they determined that some of the newly discovered animal fossils came from the same bone beds as the Homo erectus fossils. The researchers used five radiological dating methods for the animal fossils and the sediments surrounding them, including a new method that provided both the furthest and most recent dates.
The team concluded that the bones were buried between 117,000 and 108,000 years ago. The paper was published in Nature on December 19.
The researchers say Homo erectus may live longer. But about 100,000 years ago, warmer, wetter climates turned Java’s open woodlands into dense rainforests, making it difficult for Homo erectus to survive in such a changing environment. When modern humans arrived in Java about 40,000 years ago, Homo erectus may have been extinct.
Homo erectus has left an impressive legacy. Many researchers believe that when it travels in Southeast Asia, it splits into at least two additional species. The Floriss and the Luzon people found on the Indonesian island of Flores. They may also interbreed at some point with Denisovans, a close negotiable relative. In turn, the Denisovans may have mated with modern humans in Indonesia and New Guinea, perhaps just 30,000 years ago.
The researchers believe the pairings may have introduced a small amount of upright DNA into the genomes of modern Southeast Asians, which contain about 1 percent of the genetic material that does nuns, Neanderthals or Denisovans, do not appear to have come from modern humans, Neanderthals or Denisovans.
In any case, experts say, Southeast Asia is now clearly one of the most exciting places to study the origins of humans.
Related papers: https://doi.org/10.1038/s41586-019-1863-2