Traces of Hobbits
Researchers have unearthed teeth smaller than those of the Homo erectus in Java and the Homo floresiensis found in Flores. The connection between the two is still a mystery.
MIKA Rizki, 30, a doctoral student of paleontology at the University of Wollongong, Australia, just joined the excavation team at Soa Basin, Mata Menge, Flores, East Nusa Tenggara, a month before the big discovery.
Her job was to make a record of everything found by the team. After two weeks of excavation done in cooperation with researchers from the geological agency, Mika stumbled upon something major: a human tooth. "I saw a fossilized tooth. This is what we had been looking for," Mika said last month. The discovery took place in early October 2014.
That morning, as usual, Mika went around the excavation site to take note of the various findings. When she arrived at the dig being carried out by Andreas Boko, a local resident, she noticed a small object. Upon closer inspection, she suspected it was a fossilized tooth from a prehistoric human. After going through a long verification process that involved aging the tooth as well as other determinations, the discovery was published in the scientific journal Nature in June.
The tooth is a lower right molar with five points. Compared to the fossilized teeth of Homo erectus in Java, these teeth are smaller. "Both have a similar shape," Fachroel Aziz, an expert in paleovertebratae at the Geology Museum in Bandung, said at a seminar in June.
The finding of the tooth encouraged the researchers to extend the dig past the initial three-week schedule. The extension was not in vain. After further digging, they found other bone fragments that appeared to be teeth. Six more tooth fossils were found: upper and lower molars as well as two baby teeth. From their shape and the corresponding pattern, the teeth likely came from one adult and two children. Their gender could not yet be determined, but Fachroel said the teeth likely came from members of the same family. Since 1963, researchers have been searching for the teeth of prehistoric humans at Mata Menge. Mika's discovery is the first documented finding.
Iwan Kurniawan, a member of the team of paleontologists from the Geology Museum conducting the research, said the fossils were found at a depth of 2-2.5 meters below the surface. The excavation team divided the site into four square areas, each measuring 4 x 5 meters. These 'squares' were organized in a line running from north to south, "according to the direction of an ancient river," Iwan said. The Soa Basin is what remains of a crater from the eruption of Mount Ola Kile. It is 1.5-2 million years old. After the eruption, researchers estimate it took 500,000 years for any life to return to the basin.
In addition to the tooth fossils, the dig team discovered a fragment of a mandible, or the lower part of a jaw. Noting the third molars, or wisdom teeth, they concluded the teeth were from an adult smaller in size than modern men. Though the teeth were smaller, researchers attempted to link them to Homo floresiensis, a prehistoric human discovered 12 years ago at Liang Bua Cave, Flores. The cave lies about 70 kilometers west of Soa Basin in Mata Menge.
If there is a connection with Homo floresiensis, popularly called the Hobbits of Liang Bua, Fachroel suspects that the fossils found at Soa Basin came from a common ancestor. This theory is based on the age of the teeth, which are much older than those of the 'hobbits', which are between 13,000 and 94,000 years old. The fossils found at Soa Basin have been dated to 500,000-700,000 years old.
There are other scientists, however, who say the shape of the teeth found at the Soa Basin better resemble those of the Homo erectus in Java. This gave rise to the speculation that the prehistoric humans at Soa Basin came from Java.
Fachroel rejects this theory. He said 500,000-700,000 years ago, Indonesia was on the Sunda Shelf, which connected the islands of Sumatra, Java, and Kalimantan. There was also the Sahul Shelf, which brought together Maluku and Papua. When the sea level dropped, land was formed. Between those two land masses, which included Sulawesi, Halmahera and Nusa Tenggara, there was a stretch of sea with a depth of about 3,000 meters. The receding sea level did not mean much, however, as it only dropped about 200 meters.
If the prehistoric humans at Soa Basin came from Java, Fachroel said, they would have had to risk their lives to cross the Lombok Strait, the Alas Strait and the Sape Straitall of which are over 200-250 kilometers wide. "Only swimming creatures could reach Flores Island at that time," said Fachroel. Obstructed by a vast and deep sea, only good fortune could have brought them to Flores.
Seconding Fachroel, Gert van den Bergh, a paleontologist at the University of Wollongong, doubts the theory. He is unpersuaded by the idea that such prehistoric humans could have built a boat to take them to Flores. "Personally, I think that could only have happened if something unusual occurred, such as a tsunami," he said.
Fachroel came up with another hypothesis. According to him, prehistoric humans in Flores arrived from the north or south by a different route, such as from the Philippines or Sulawesi. "This is the amazing thing. It is estimated that those humans who lived 750,000 years ago could have reached the Flores Islands," he said. His hypothesis still needs to be tested.
The habitat of prehistoric humans found at Mata Menge 700,000 years ago can be determined from the many fossils discovered. That habitat consisted of grassy fields and a constant supply of fresh water. The likely cause of death of the prehistoric humans at Soa Basin is connected to a volcanic eruption. "Possibly an eruption of a hillock of Mount Ola Kile, as the fossils were found in a layer of volcanic ash," Fachroel said.
Researchers guess that the prehistoric humans were hunting at that time. Even so, the cause of death cannot yet be determined, as not enough information on living conditions has been gathered. "It can be confirmed that their habitat was an open area, a wide plain," said Fachroel. He downplayed the possibility that this prehistoric human family died of illness, as diseases from hundreds of thousands of years ago were not as developed as they are now. If fossils of other bones can be found, such as a leg, the cause of death will become clearer.
At present, the team of researchers is unable to say what type of prehistoric humans were at Soa Basin. "Currently it is still being referred to as just in the Homo genus," Fachroel said. At present, tooth and jaw fossils are not enough to determine anything further about the origins. So if the prehistoric humans at Soa Basin are not Homo erectus or Homo floresiensis, is this a new species of prehistoric human? Fachroel thinks elements of an answer are not yet complete.
Tri Artining Putri, Anwar Siswadi (The New York Times)