On 10th September 2015, palaeontologists discovered fossil remains of some ancient form of human lives Homo naledi at the Rising Star Cave in Cradle of Human System site, South Africa. The discovery has the potential to shed some fresh light on our understanding of human evolution, as the unearthing has brought some striking details about the behaviour of Homo naledi, which is so far considered unique to our human race.
When our scientists had believed that burying the dead is a behaviour unique to the human species, Homo sapiens, and not any other related live forms, the fossil remains found came as a big surprise as they have been confirmed to be the remnants of the buried dead of naledi species.Scientists have always believed that we as human life forms evolved from our primitive ancestors and we have been able to uncover a lot of evidence to support this belief. There has been no concrete evidence saying this is where it all began from. Maybe we never would be able to. This is where the discovery of Homo naledi stands significant.
The discovered life form seems like one of the primitive members of our genus Homo, yet they resemble some very human-like features that could place them in our genus Homo, says a senior author from University of Wisconsin, Madison. Thus, they represent a combination of human-like and non-human like features, which has become more puzzling about the new species. For instance, brain size, trunk, shoulders, hip and the curved fingers resemble that of the features of primitive men like Homo habilis. But the features of forelimbs and hind limbs resemble that of the modern human forms like Neanderthals.
The newly founded fossil remains haven’t been yet dated as it includes some complexities, which will be discussed later. If the remains are dated back 2 million years ago, then what the scientists have exhumed is nearly the oldest of our genus Homo, says a research paper of palaeontologist Lee Berger from University of Witwatersrand and his colleagues. Otherwise, it would be a relatively old species that could have inhabited the earth in a time nearer to that of the Hobbits (Homo florosiensis), suggests Berger and his colleagues in the paper.No matter what the date is, the mixed human and non-human characteristics of naledi species suggest that the origin of modern man is so complex that would shake-up the studies and classifications so far our palaeontologists and scientists have made.
Why is dating the naledi species so complex? There are many methods to date back the fossils found including radiocarbon dating, electron spin resonance (ESR), DNA found in the fossils, uranium found in calcite sheets of the cave walls and floors etc. In case of Homo naledi, every technique is held back by some complexities. Yet, researchers are not giving up.
Carbon dating works well on fossils that are 50,000 years old, and naledi remains seem to be much older. Testing if the remains are older than that period may require destroying them, which is undesired, says Chris Stringer, British Anthropologist. Similarly, all the other techniques have their own difficulties. The Rising Star crew may adopt a technique monitoring the magnetic minerals of the fossils that would have realigned several times along with the magnetic field of the Earth. This is considered a laborious task as well.
History says that there have been huge contradictions in the results predicted by various techniques used to date the old remains. For example, the date estimates of Australopithecus skeleton found in South Africa in 1990 differed by 2 million years through the different methods. Thus, the challenge now is to find a result that is unwavering with the type of technique used.The challenges faced are numerous in finding these remains as well. The Rising Star cave system has several chambers, and the fossils are found 90 metres away from the entrance. The area where the remains are found needs to be reached by crawling across a narrow opening of size 18 cm (see picture above). Lee Berger made an announcement on social media that he is looking for skinny paleoanthropologists who can climb and crawl through such a narrow opening. Six females were selected, and the team collected some 1550 specimens of fossil fragments that make up 15 skeletons including adults, children, both males and females.
Acclimatised to address such challenges, certainly there is a lot more this discovery of naledi species opens the door to.
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