Found: The Most Complete 2-Million Year Old Human Fossil in the ‘Cradle of Humankind’
By on July 13th, 2012

The dead do speak. And it is the paleontologists who go around trying to eavesdrop on such a silent conversation. Most of the times, the sentences are broken. Once in a while, a whole sentence is found and much jubilation follows. One of these sentences, which I use as an euphemism for ‘skeletons’ here, has been found in the so-called ‘Cradle of Humankind’, north of Johannesburg. The question: what does it really say?

The skull of the A.sediba individual. Look at the white spot on the rock – that’s the hominid tooth.

Where the individual fits – in space and in time

The skeleton, nestled lightly between hard rock, is a hominid skeleton and is the “most complete early human ancestor skeleton ever discovered”. It is about 2 million years old, which puts it right at the beginning of the time when the species of the genus Homo – whose members walked on two legs and had less hair than the apes – were beginning to emerge. The oldest known members of the Homo genus are Homo habilis, whose skeletons date back to 2.3 million years ago. Homo erectus, the first species of the Homo genus, to walk upright emerged later around 1.6 million years ago.

The skeleton is that of Australopithecus sediba species. It is widely believed that one of the species of the Australopithecus genus evolved to give the Homo genus, which leads to us. One of the species is our ancestor. A. sediba is probably not!

Skeleton – such a completeness was never there before

The skeleton reveals that the individual was learning to walk upright, fitting right into that snug spot on the evolutionary ladder between becoming merely bipedal and becoming bipedal and upright. The individual is an infant aged between 9 and 13 years and it could be of either gender. This is actually the completion of an expedition that revealed part of this same fossil way back in 2009.

Prof. Berger, a lead scientist in this expedition is thrilled:

We have discovered parts of a jaw and critical aspects of the body including what appear to be a complete femur [thigh bone], ribs, vertebrae and other important limb elements, some never before seen in such completeness in the human fossil record.

The discovery was a stroke of luck, it seems. The team spotted a piece of hominid tooth embedded in black stone. They excavated further to reveal a complete skull!

Questions?

The critical question remains: was A.sediba a direct ancestor to us? The skeleton hasn’t started singing out its secrets yet. It will soon!

The Cradle of Humankind, as romantic and innocent as it might sound, is actually a deep pit containing many caves, where a large number of individuals of A.sediba and some other species are had fallen and died. For scientists studying human origins, this is a goldmine. The site has been the continuous paleontology site and has now been declared a World Heritage Site.

Now, just to wait to hear the dead speak…

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Author: Debjyoti Bardhan Google Profile for Debjyoti Bardhan
Is a science geek, currently pursuing some sort of a degree (called a PhD) in Physics at TIFR, Mumbai. An enthusiastic but useless amateur photographer, his most favourite activity is simply lazing around. He is interested in all things interesting and scientific.

Debjyoti Bardhan has written and can be contacted at debjyoti@techie-buzz.com.
 
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