New Fossils of Early Human Ancestor Found Embedded in Rock

When first discovered in the deroofed Malapa Cave of South Africa, the news of the 1.98-million-year-old fossilized remnants of a new early homin (early human ancestor) species called Australopithecus sediba (A.sediba) reverberated throughout the world of human evolutionary scholarship. It was perhaps the most sensational find since the discovery of "Lucy", the benchmark Australopithecus afarensis discovered by Donald Johanson in 1974 in Ethiopia, thought by many to be an early species predecessor to the genus Homo, or humans. Now, scientists from the Wits Institute for Human Evolution at the University of the Witwatersrand in Johannesburg are announcing the discovery of yet more fossil elements they believe belong to one of the new Australopithecus sediba species individuals, the remains of a child nick-named "Karabo".

"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," says Berger. "This discovery will almost certainly make Karabo the most complete early human ancestor skeleton ever discovered. We are obviously quite excited as it appears that we now have some of the most critical and complete remains of the skeleton, albeit encased in solid rock. It's a big day for us as a team and for our field as a whole."

About one meter in diameter, the rock, first collected nearly three years ago, was deposited in the Wits (University of the Witwatersrand) laboratories until its hidden fossils were discovered early last June of 2012. Justin Mukanku from the Wits Institute of Human Evolution first noticed what appeared to be a hominin tooth embedded in the rock. Then, Berger and wife Jackie Smilg, a radiologist at the Charlotte Maxeke Hospital in Johannesburg, scanned the rock in a state of the art CT scanner. From that point, the initial tooth discovery ballooned into a number of fossil finds. 

______________________________________________________________________________________________________________________

Lee Berger and co-worker with the rock containing the skeleton fossils believed to belong to Karabo. Photo courtesy Lee Berger and the University of the Witwatersrand. 

______________________________________________________________________________________________________________________

Justin Mukanku from the Wits Institute of Human Evolution first spotted a hominid tooth in the rock. On the other side (shown here) are antelope fossils. Photo courtesy Lee Berger and the University of the Witwatersrand.

______________________________________________________________________________________________________________________

The small tooth (in the center) that was discovered and led to the discovery of the skeleton in the rock. Photo courtesy Lee Berger and the University of the Witwatersrand.

______________________________________________________________________________________________________________________

A probable hominin fibula (circled) in the stone block, as revealed by the CT scan. Note the shaft of a probable femur just above and to the left. Photo courtesy Lee Berger and the University of the Witwatersrand.

______________________________________________________________________________________________________________________

The fossil remains of Karabo were not the only specimens uncovered during exploration of the Malapa site. More than 200 other individual bone specimens have been recovered, representing two children, an infant, and at least two adults. Karabo (catalogued as "MH1", or Malapa Hominid 1), comprises, along with the elements of a second individual, the most complete assemblage of fossil elements for a single Malapa site individual. The second most complete is an adulte female (MH2). The Karabo collection comprises a preserved skull and most of the right side of the skeleton, including ribs, the vertebral column, shoulder girdle, arm, pelvis and legs – and now with the most recent discovery – a complete femur and a number of other skeletal elements. Identified by Berger and other scientists as a new species, the significance of A. sediba is the fact that it shows a unique combination of characteristics which distinquish it from other species – sharing morphological features identifiable with theAustralopithecus genus, considered a more ape-like precursor to humans, and also those of Homo, our own genus which includes other early human species such as Hom erectus and Homo neandertalensis(Neanderthals). It has been suggested that A. sediba represents the best candidate, thus far, for the immediate ancestor of the genus Homo. (See Malapa: A Glimpse into the Ancient Past in the Popular Archaeology Magazine 2012 Discovery edition for the detailed story).

______________________________________________________________________________________________________________________

The Malapa cave site. Photo courtesy Lee Berger and the University of the Witwatersrand.

_____________________________________________________________________________________________________________________

The most complete Malapa skeleton finds. Left, MH2, the adult female. Right, MH1, Karabo, the child. Photo courtesy Lee Berger and the University of the Witwatersrand.

______________________________________________________________________________________________________________________

Live Science

The rare completeness of Karabo is not the only first. Berger, the University of the Witwatersrand, the Gauteng Provincial Government and the South African national government plan to allow open access to science and the public as they explore and uncover the fossils live, captured on video and shown to the world in real time. For the first time, this will allow members of the public and the scientific community to share in the discovery as it unfolds. It will all take place in a laboratory studio at the Maropeng Visitor Center in the Cradle of Humankind World Heritage Site, in collaboration with the National Geographic Society. Whether they are in person at the Maropeng Visitor Center or viewing it over the internet, they will see it as it happens. "The public will be able to participate fully in Live Science and future discoveries as they occur in real time – an unprecedented moment in palaeoanthropology," explains Berger. "The laboratory studio will be also linked to laboratories at Wits University and the Malapa site."

In addition, Berger and collaborators hope to quickly expand on the initiative.  "We intend to create virtual 'outposts' in major partner museums around the world," says Berger. "These outposts will allow visitors to these partner museums the chance to interact with scientists in real time in a way we simply could not conceive of a few years ago. It is anticipated that the laboratory and virtual infrastructure will be built within a year, expanding our ambitious tourism and smart province infrastructure programme."

A virtual outpost will be established at the Shanghai Natural History Museum later this year, and negotiations have already begun with the Shanghai Science and Technology Museum, the Natural History Museum in the United Kingdom and the Smithsonian in Washington, D.C. 

Republished with permission from Popular Archaeology, a purely online magazine that is "a 100% online periodical dedicated to bringing archaeology to the public." Find more content here: http://popular-archaeology.com/