A Homo erectus skull found at the Ngagdog site in the 1930s.
The timeline of the Homo Erectus has become clearer after scientists have excavated the last of the species in Central Java, Indonesia.
Evolved about two million years ago, Homo erectus is considered as the first Hominid species to walk uprightly. And the new study published in the journal Nature on Wednesday claimed that they probably still existed around 100,000 years ago.
The fossils were found in at the Ngandong site, the same site where 12 Homo erectus skulls were retrieved by a Dutch team in the 1930s. Because of the confusing geology and absence of advanced dating techniques, the timeline has become a mystery among scholars, resulting in different results. A 1990 study even claimed that it has overlapped with the timeline of modern humans by still existing around 53,000 to 27,000 years ago.
But now, it has become clearer after a research team led by Prof Russell Ciochon of the University of Iowa in Iowa City began reanalyzing the site in 2006. And they came up with a result of 117,000 to 108,000 years old, making it the youngest known record of Home erectus all over the world.
Human evolution expert Chris Stringer from London's Natural History Museum praised the comprehensive study for its strong evidence to prove its accuracy.
A Long-living Species
Since excavation has begun, there were at least 200 fossilized Homo erectus have been found all over the Java, with the first one found at Trinil site in 1891. The oldest known lived around 1.7 million years ago.
Ciochon called the Homo erectus as "one of the most successful hominids that ever lived" because of its massive timeline and geographic distribution.
According to the researchers, the diaspora became possible through the land bridge that connects Java from the mainland Asia. The said bridge has disappeared after the glacial period.
The Homo erectus is considered as the oldest species found to be related to humans due to many similar traits. However, Ngandong fossils were observed to have larger skulls compared to other fossils.
But according to Ciochon, they cannot tell whether or not these ancient species were smarter from the groups found in other areas.
It is noted that a previous study claimed that having a bigger brain does not make a species smarter by default.
More stories to tell
When the site was first excavated in the 1930s, the scientists also found at least 25,000 other fossils. According to this recent study, it just tells how the Homo erectus went extinct: because of climate change.
Ciochon explained that the upright species were highly dependent on open areas like savannah and too vulnerable on rainforest because they cannot find the food their normally eat or they are more vulnerable to predators. After the ice melted, floras and faunas flourished all over the Java region, resulting in the end of the species and the rise of Homo sapiens, which became the only Hominids that survived in the forest.
But for the fossils in the Ngandong site, scientists believed that they were killed by a natural disaster, possibly by a lahar -- a mudslide caused by a volcano. Evidence has shown that these remains were carried by a current and got buried underground.
And lastly, the researchers have also found a possible new species: the Denisovans, a human-like species which was only identified through a few bone samples.
The team explained that it is possible that this species have ventured as far as Southeast Asia and possibly interacted with the Ngandong Homo erectus, but it will require a lot more research to prove.
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