When fossil hunter Bernard Ngeneo came across the remains of this fossil, only the upper portion of the orbits were protruding from the ground. Excavation revealed one of the best preserved skulls of this time period, and one of the most striking early human fossils of any age.
KNM-ER 3733 represents a mature female of the early human species Homo erectus. The sex identification comes from a comparison of the anatomical features of her face with several other crania from Koobi Fora: KNM-ER 3883 (male), and KNM-WT 15000 (also male), found on the opposite side of Lake Turkana. The features of KNM-ER 3733 are markedly less robust. It’s known to be an adult on the basis of the cranial sutures (which were fully closed), the extent of the wear on the teeth, and the eruption of the third molars before the individual’s death.
It’s a real head-scratcher. The shapes of human skulls from a narrow strip in Mexico reveal that first arrivals to the Americas may have kept to themselves, even when there were no geographical barriers that would have prevented them mixing.
Mark Hubbe and Brianne Herrera at the Ohio State University in Columbus and their colleagues took detailed measurements from a series of 800 to 500-year-old skulls unearthed in three regions of Mexico. They then looked at equivalent measurements from skulls found at a number of sites across North and South America, East Asia and Australasia and analysed how skull shape varied with location.
Skulls from two of the Mexican regions – Sonora and Tlanepantla – clustered together in the shape analysis. But skulls from the third region, Michoacán, were different. The variation was on a scale normally seen between two populations that have been separated for millennia, often because they have settled in regions that are thousands of kilometres apart. Yet the distance between Michoacán and Tlanepantla is under 300 kilometres.
It’s an astonishing discovery, says Hubbe. Mexico was first inhabited at least 10,000 years ago, and the founding populations may well have had different genetic histories before they settled in the area. Crucially, the populations seem to have been so reluctant to interbreed that those genetic differences were still apparent just 500 years ago. “For whatever reason, these differences have been maintained for thousands of years,” says Hubbe.
Mexico lacks obvious geographical features that could have kept people apart – but formidable cultural and language barriers might have existed, says Hubbe.
“When it comes to population history, a whole host of scenarios are possible,” says Noreen von Cramon-Taubadel of the University at Buffalo, New York. “We see instances even in modern populations where neighbouring groups live in close geographic contact yet do not mix extensively in terms of marriage.”
“The Lagoa Santa material is unique in the entire New World,” says André Strauss at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who was also involved in the work. “It presents abundant, well-preserved, old skeletons with reliable associated archaeological context.”
The researchers discovered that these earliest South Americans – the “Palaeoamericans” – had skull shapes that are distinctly different from those of most indigenous South American populations alive today.
“The differences between the Palaeoamericans and today’s South Americans are so large that they cannot simply have appeared in 10,000 years,” says Hubbe.
In other words, the Palaeoamericans cannot simply have evolved into today’s indigenous South Americans. Instead, the researchers estimate that the two populations split apart from a shared ancestral population at least 20,000 years ago, offering a much larger time window for the two groups to develop distinct skull features.
Because the consensus is that the Americas were not inhabited 20,000 years ago, this conclusion implies that South America may have been colonised in at least two distinct waves – one represented by the ancient people at Lagoa Santa and another by today’s indigenous South American populations.
“It is great to see this new analysis of morphological data,” says Pontus Skoglund at Harvard Medical School, an author on the 2015 study. “It reiterates that there is something interesting about the peopling of the Americas that we don’t quite understand yet.”
Everybody has heard of the Elgin Marbles and the debate surrounding the right’s of countries to those artefacts. These marbles are famous the world over but this story is repeated many more times not just in archaeology, but palaeoanthropology also. Zambia was once a colony of the British Empire and it was during that time that a certain hominin skull E 686 was uncovered. This skull is now lies in the vaults of the South Kensington Museum, London. In Zambia, Deputy Minister Susan Kawandami (pictured) recently reported before the Zambian Parliament that years of talks failed to secure the return of E 686 to Zambia with the Natural History Museum, London prepared to make copies of the skull instead. Kawandami will now establish new discussions through UNESCO, while Minister of Chiefs and Traditional Affairs, Nkandu Luo will visit London to establish a dialogue with the Trustees of the Museum.
If the Natural History Museum is ever to return the fossil, one thing is for sure, Zambia will have to convince the London Museum, that it is proactive in heritage (particularly palaeoanthropological) promotion and will ensure great care for the priceless skull. Which is currently not the case. The famed locality has no interpretative centre, no sign, no indication that two pivotal hominin bones – E 686 (Skull) and E 691 (tibia), were uncovered there. On the 17th of June 1921, A. S. Armstrong and A. W. Whittington uncovered those remains at Mutwe wa Nsofu, Mulungushi Road, Kabwe, Zambia. That same year, the fossils were given a new human species name – Homo rhodesiensis. This species has, thus far, only ever been found in Africa and it is a species that is seldom used by palaeoanthropologists. Most consider it a variation of Homo heidelbergensis. A key species that diverged into Homo sapiens (in Africa)and Homo neanderthalensis (in Europe). From about 1.5 million to 500,000 years ago, is a time that palaeoanthropologists have difficulty understanding due to the particularly patchy fossil record. So, what I have described is quite simplistic and many would argue over the exact details. The two fossils represent two adults males, that lived around 1 million years ago. Sadly, given they were found in the 1920’s, excavations in the field of human evolution were in their infancy and so, grossly inaccurate. The only way to date the site was through biostratigraphy. By looking at the animals that were found in the layers in which the fossils were found, later palaeoanthropologists compared those assemblages to strata at other sites which were radiometrically dated. The Kabwe stratigraphy was quite similar to Bed IV at the Oldupai Gorge which was dated to between 780,000 years to 1.3 million years.
Zambia’s National Heritage and Conservation Commission (NHCC) is now in the process of rehabilitating the site. Chief executive officer of the commission, Collins Chipote warned that though the site was intact, it needs to be secured and developed. A Kabwe Mining museum was commissioned by Minster Nkandu Luo (pictured), which will be run by the Lead-Zinc Mining company Enviro-Processing Ltd. a subsidary of the giant Berkeley Mineral Resources PLC. More effort is required on the part of Zambia to show that they have the determination to celebrate their priceless heritage and right now, there seems to be no action, but plenty of talking.