Scientists from Johannesburg's Wits University in collaboration with other scientists and volunteers revealed on 10 September 2015 the discovery a new species of human ancestry, Homo Naledi.
The fossils were first discovered in the Dinaledi Chamber at Maropeng in October 2013 during a relatively short excavation.
Professor Lee Berger's team recovered an extensive collection of 1550 hominin specimens, representing nearly every element of the skeleton multiple times.
According to the scientists, the collection is a morphologically homogeneous sample that can be attributed to no previously-known hominin species.
The above and along with the fact that the Homo naledi fossils are the largest collection of a single species of hominin that have been discovered in Africa so far is what makes the discovery significant.
Below are 7 facts you probably need to know about one of the most significant fossil discoveries of the past five decades.
1. Underground Astronauts
The chamber of the caves that the Homo naledi fossils were found in was only accessible by skinny people (as Professor Lee Berger explained) as one of the pathways was only ten inches (25.4 centimeters) in height.
Deep in the Dark Zone | Jasont Treat (National Geographic); National Geographic Maps
None of Prof. Berger's team members at the time could fit through so he put out word on Facebook stating "Skinny individuals wanted, with scientific credentials and caving experience; must be 'willing to work in cramped quarters.'"
Surprisingly, within approximately a week Berger heard from nearly 60 applicants. He chose the six most qualified which were all young women.
Underground Astronauts | John Hawks (Wits University)
He called them “underground astronauts.”
2. Primate vs. Hominin
There's been some confusion which has resurfaced since the discovery of Homo naledi. This confusion is captured by two prominent South Africans who took to Twitter and radio to express their disapproval that they "didn't evolve from apes or baboons".
First, it is former COSATU leader, Zwelinzima Vavi, who stated in a tweet:
I have to agree with Motshekga - this story that my ancestors were baboons does not sit well with me. Have any body seen a baboon my height?— Zwelinzima Vavi (@Zwelinzima1) September 11, 2015
His tweet (as he states) is inspired by what Dr. Mathole Motshekga, Founding President of the Kara Heritage Institute, said in a radio interview which you can listen to below.
I agree we have to tolerate and respect each other's belief systems but at the same time, there is a difference between apes / baboons (primates) and hominids as Prof. Lee Berger explained to Dr. Mathole Motshekga in a Radio 702 interview with Redi Tlhabi.
Motshekga says #HomoNaledi represents findings of monkey bones. Prof Berger tells him monkeys are primates & Naledi hominid. MM keeps quiet.— Redi Tlhabi (@RediTlhabi) September 10, 2015
There is a difference between primates (e.g. baboons, monkeys etc.) and hominins, which makes the above statements ironic in that all three actually agree with each other in that humans didn't evolve from baboons or monkeys.
More importantly (hence scientists continue their search for the missing link), Homo naledi species is related to humans, although not closely so.
A Place in Time| Jason Treat (National Geographic). Source Wits University
3. Largest Fossil Discovery In Africa
Approximately 1,550 specimens of hominin fossil remains were found in the Dinaledi Chambers at Maropeng with Prof. Berger and his team still believing there is much more to be still discovered.
Scientist Marina Elliott with Homo naledi | Wits University
The fossil discovered so far are believed to be of skeletons from at least 15 individuals.
According to eLife magazine, this discovery constitutes one of the greatest and most complete discoveries of hominins rests found until this date.
4. An Old Species
Although more work still needs to be done in determing the exact age of the fossils discovered, Prof. Lee Berger has said that Homo naledi’s anatomy suggests that it emerged at or near the root of the Homo group, which would mean the species is approximately 2.5 million to 2.8 million years old.
Professor Lee Berger, leader of the Rising Star Expedition at the site | Wits University
Since the age of the bones discovered is yet to be determined, they could be younger.
5. Mixed Traits
Evidence points to Homo naledi having been walking upright but it also possessed mixed traits from both humans and apes.
A New Kind Of Ancestor | Art by John Gurchie. Source Wits University
Homo naledi's hands and feet look like they are from the genus Homo, but the shoulders and the small brain are suggestive of Homo’s more ape-like ancestors according to Prof. Berger and his team.
Given how the discovered fossils have curved hands, this suggests that Homo naledi had the ability to use tools because of the extremely curved fingers.
Homo naledi hand | Johan Hawks (Wits University)
According to the scientists, Homo naledi's hands are more curved than most other species at such early state of hominin.
Suggesting they had climbing and tool-using capabilities.
7. Burial Ritual
Perhaps the most fascinating yet still speculative (according to some critics) is the suggestion that Homo naledi buried the dead, behaviour and ritual only known to be practiced by modern humans.
An H. naledi group disposes of one of their own in Rising Star cave in this artist’s depiction | Art by John Foster. Source Wits University
Why and how did Prof. Berger and his team reach this conclusion?
The number of bodies, their location, and the difficult access to the cave made them conclude that Homo naledi species deliberately disposed dead bodies in caves as a way of burying them.
If further substantiated, this could have important implications for understanding the origins of modern human rituals and behaviour.