The newest addition to our family – Fossil Friday

It is quite rare that we can add a new member to the Homo family, but it is what happened last year. Homo naledi, a long lost cousin of our species, has been added to the already complex family tree of the genus Homo. At Sci&Fi, we just wished these other humans were still alive, it would be such a fantastic world to have a mirror of our own humanity in modern times. Who knows how History would have unfolded? But let us not go off topic…

Homo naledi, assemblage of skeletal remains (taken from Berget et al.)

More than 15 000 bone pieces of, at least, 15 individuals, this is the extraordinary find of a team of archaeologists in 2013 that got published in 2015 that lead them to create a new species, Homo naledi. Naledi means “star” in the Sotho language (spoken in South Africa) and surely this new species is one in the world of palaeontology where fossil humans are difficult to come by. H. naledi‘s remains were discovered in South Africa in a large cave system called the Rising Star Cave System. It is difficult to determine to which other species it is close to based on its bones. Indeed, naledi has a confusing set of traits : some pertain to later hominins and some to earlier ones. For instance, its small brain case, its shoulders or even its fingers are reminiscent of some late australopithecines or early Homo, like H. habilis. Some other parts of its body resemble ours, modern humans. Based on the bones they were estimated to have been around 1.45 meters tall and weight between, approximately, 40 to 56 kilos ; a short human all in all. The fossils have not been dated yet and since the bones don’t tell a clear story there is no way of knowing when they evolved. So major questions still remain : how ancient could they be and where could they fit in the human evolution ?

 

Panel 3 - rising star cave system

Location of the Rising Star cave system. Cross section through the cave (Dirks et al.). View from above of the Dinaledi Chamber and its access point (Dirks et al.).

All of the remains were found deep in a cave system and only in one single chamber, bizarre feature… The preliminary analysis of the geological context indicate that the hominins were not washed there. It could have been the case if water had deposited them there, flowing through fractures in the caves. It was clear either that they had not been transported there by other creatures. Indeed, other than H. naledi, no other big animals’ remains were found in the caves. Additionally, none of the bones had teeth or scratch marks that would be consistent with predators or scavenger. Consider these few points too, there were no remains of tools, of fire or any other traces of occupation of the chamber, just the remains. And it’s in a cave, far away from the entrance, in the dark zone (= no light ever reaches there), meaning that people had to purposely climb all the way through, probably with artificial light.  There is but one hypothesis left to explain why they were found so deep in the cave system: they were intentionnally deposited here… Although disputed, this looks like a burial site. And if a hominin buries its dead, it means that it possesses beliefs, and rituals associated with it, in brief they were intelligent. To top up the mystery, naledi‘s brain case was no bigger than our early ancestor Homo habilis… Yet another archaeological find leaving more questions than answers!

 

At Sci&Fi, we’ll definitely be on the look out for more information, and we’ll keep you posted on what we learn about our distant cousin.

Adrien for Sci&Fi, over and out.

References:

Berger, L.R. et al. (2015) Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa. eLife.
Dirks et al. (2015) Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi Chamber, South Africa. eLife.
Striner, C. (2015) Human evolution: The many mysteries of Homo naledi. eLife.

Visual Credits:
Figure 1 from Berget et al.
Panel : world map arranged by Sci&Fi. Figure 2 B and Figure 2C by Dirks et al. (2015).

2 Comments

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