Human fossils – a jawbone and a skull – found just a few meters from Tam Pa Ling cave near Annamite Mountains in northern Laos reveal the physical diversion of early modern humans.
These human fossils, whose age is estimated between 46.000 and 63.000 years, provide us with information about this species’ migration in Southeast Asia, which happened a lot earlier than scientists thought.
The skull, found in 2009, provides the first evidence of modern humans in Southeast Asia, therefore it is the oldest human fossil in the area.
Additionally, it appears to have fully modern features. The jaw was excavated in 2010 at a small distance from the skull. According to Professor Laura Shackelford of the University of Illinois, the jaw has a surprisingly small size.
Moreover, it combines characteristics of modern human anatomy, like protruding chin, with traits of the archaic Neanderthals, like thick bone structure. Albeit, scientists explain that this morphological variation is common in human fossils found in China, Eastern Europe, and Africa.
Researchers already know that many uncategorized species have existed in the past.
In 1976, parts of a skull and teeth were found in Xujiayoa, China. These human fossils provided important information on human origins.
The dental remains, which belonged to four individuals, were examined by research groups. After comparing them with 5.000 teeth of known species, they reached the conclusion that these teeth matched none of them.
In 2013, the genome of Denisovans, our ancestors, was found to contain a segment of DNA that came from an unknown human species. According to scientists, this possibly happened due to uncontrollable interbreeding among the populations of Europe and Asia 30.000 years ago.
Another example is the prehistoric population of Red Deer Cave in China, dating back to 14.500-11.500 years. Although their characteristics are slightly different from modern humans, researchers cannot yet classify them as unknown species.
After taking into consideration the existence of Neanderthals in Europe, the presence of Denisovans in Asia, and Homo floresiensis in Indonesia, the human fossils found in Laos indicate the existence of a fourth group from Eurasia that probably interbred with the Denisovans.
It was a very primitive one, which is currently unknown to scientists. So, the question that remains to be answered by the researchers is whether this group emerged after interbreeding between modern and archaic populations or whether the abnormalities in its characteristics were a part of the evolution procedure.
Further research continues has to be done while scientists are in the middle of a constant debate trying to explain the existence of the primitive fossils found in Laos.
Nevertheless, they all agree that these findings provide them with valuable insight that will hopefully lead to answers on the origins of human existence on earth.
Featured image: Demeter F, Shackelford L, Westaway K, Duringer P, Bacon A-M, et al. (2015) Early Modern Humans and Morphological Variation in Southeast Asia: Fossil Evidence from Tam Pa Ling, Laos. PLoS ONE 10(4): e0121193. doi:10.1371/journal.pone.0121193 / CC0
