DENPASAR, KOMPAS — Fossils of Homo erectus bones and hand axes found in Bumiayu, Brebes regency, Central Java, are estimated to be 1.8 million years old. The fossil is older than the Homo erectus in Sangiran, which is 1.5 million years old. This finding has the potential to revise the theory of Homo erectus\' first arrival in Java based on the “Out of Africa” theory.
A few months ago, the Yogyakarta Archaeological Center (Balar) received a report from the owner of the Bumiayu-Tonjong Museum, H. Rafly Rizal, and fossil conservationist, Karsono, that they found several fossil bones. The findings were conveyed to the Preservation of the Ancient Sangiran Site and Yogyakarta Balar senior archaeologist Prof. Harry Widianto.
"After I checked it, it turned out that the bone fossils from Kalibodas, Bumiayu, were fossils of human bones in the form of three groin bones [caput femural], fragments of lower jaw with tooth roots and fragments of thigh bones, the medium part. Its fossilization level is complete. The bones have become minerals, their color is black," Harry, who is also chairman of the Plio-Plestosen Migration Archaeological Research Team at Bumiayu-Prupuk-Semedo area on Friday (5/7/2019), told Kompas in Bali.
To ascertain the context of the findings, the researchers plunged into the field on 17 June-4 July 2019 in Kalibodas, Bumiayu, and its surroundings. After correlating with the stratigraphy or arrangement of rock layers in the earth\'s crust, the researchers confirmed that the human bones originated from the lowest part of the Kaliglagah formation layer, which means it is from 1.8 million years ago. Seeing its time, the fossils were bones of Erectus or humans that “walk upright”.
"So far, people say Homo erectus originated from Africa 1.8 million years ago which then spread to Europe, Central Asia, China and wandered to Java Island [Sangiran] around 1.5 million years ago, which was found in layers of Pucangan formation in the form of black clay. But, this discovery shows another fact that Homo erectus turned out to have been around 1.8 million years ago," said Harry.
For now, the age estimates of Bumiayu Homo erectus fossils still use a relative calendar system. Some samples will undergo 40 and 39 argon-argon calendar tests in France and vision tracks in China, the results of which will come out in the next six months.
In addition to fossils of human bones, the researchers also found handy axes from andesite rocks originating from the same era as Bumiayu Homo erectus. So far, the oldest artifacts in Indonesia have been found in Dayu, Sangiran, at 1.2 million years old. The handy axes were usually used for handling animal catch from hunting, especially for breaking bones.
Appear first
The Bumiayu area had been an object of study in 1920-1930. At that time several fauna species aged 1.6 million to 2 million years were found, older than the fauna in the Central Java and East Java regions. Animals that lived at that time, for example Sinomastodon (ancient elephants), Hexaprotodon (water horse), Geochelon (giant turtles), Bu-balus paleo karabau (buffalo) and Bos bubalus (banteng).
About 2 million years ago, most of Central Java and all of East Java were below sea level. The Bumiayu area has been partially lifted. Two million years ago, Bumiayu-Prupuk Line (Brebes)-Semedo (Tegal) was a beach on the border of Central Java-West Java. The new island of Java was totally lifted 1.65 million years ago.
According to Harry, this discovery could potentially revise Homo erectus\' first landing theory in Java based on the “Out of Africa” theory. It was previously believed, the age of Homo erectus in Sangiran was the oldest. "This situation [the finding of Bumiayu fossil] proves, Sangiran is not the first landing when Homo erectus came for the first time on Java," he said.
The discovery of fossils and artifacts of Homo erectus in Bumiayu also initiated a new understanding of the arrival of humans on the island of Java according to the “Multi-Regions” theory, which states that Homo erectus arrived in a number of places and experienced local evolution. Apart from Indonesia (Bumiayu), in a number of other countries, such as Africa, Europe, Central Asia, and China, Homo erectus fossils aged 1.8 million years old have also been found.
An overview of the arrival of Homo erectus in the archipelago is increasingly interesting with the discovery of 700,000-year-old human fossils in the Soa Basin, Mata Menge, Flores, East Nusa Tenggara, by the Joint Team of the Geology Agency’s Geological Survey Center and the Wollongong University, Australia, 2016. Thomas Sutikna, an archaeologist with the Wollongong University, Australia, said the fossil discovery shows how early humans managed to cross the ocean to the eastern Indonesian archipelago. (ABK)