Stone Pages - Archaeo News (Africa)

Earliest modern human

Sun, 15 Jan 2012 10:41:57 +0100

Palaeo-anthropologists agree that modern humans evolved in Africa about 200,000 years ago, yet fossil evidence for the earliest examples is scarce. One problem is the difficulty in recognising true modern humans in the fossil record: At this time, many thought to be early members of our species possess a mix of modern and primitive traits. For some, this means our species once had a greater range of physical variation than today - for others, that more than one species of Homo may have lived in Africa at this time.
Despite these challenges, there are several candidates for the earliest known members of our species.
Omo I and II (195,000 years ago): In 1967, a team led by Richard Leakey discovered possible Homo sapiens fossils in the Kibish Formation near the Omo River in southern Ethiopia. Re-analysis in 2005 revealed they are 195,000 years old - the oldest fossils assigned to Homo sapiens. Researchers largely agree Omo I was a modern human; flat face, fully formed chin, high forehead and globular brain case. They are less certain about Omo II, with its thicker cranial bones and sloping forehead.
Herto (160,000 years ago): Tim White of the University of California at Berkeley and colleagues unearthed three largely complete skulls in the Middle Awash region of Ethiopia in 1997. They appear quite modern, but because certain traits are outside the range of modern variation, they were placed in their own subspecies.
Qafzeh and Skhul (~100,000 years ago): In the 1930s, researchers working in these caves in northern Israel found the remains of at least 30 individuals, a few purposefully buried. Some suggest they represent an early migration out of Africa, but like Omo II some are difficult to classify. The primitive traits in this population might have resulted from interbreeding with Neanderthals, who also lived in the region at this time.

Edited from Smithsonian.com (11 January 2012)

Earliest human sleeping mats found in South Africa

Mon, 12 Dec 2011 09:35:48 +0100

A team working in South Africa claims to have found the earliest known sleeping mats, made of plant material and dated up to 77,000 years ago - 50,000 years earlier than previous.
Early Homo sapiens were nomads who lived by hunting and gathering, often creating temporary camps. One of the best studied of these is Sibudu Cave, a rock shelter in a cliff face above South Africa's Tongati River, about 40 kilometres north of Durban. Sibudu was first occupied by modern humans at least 77,000 years ago, and continued a favoured gathering place over the following 40,000 years. A team led by Lyn Wadley, an archaeologist at the University of the Witwatersrand, Johannesburg, has been excavating at Sibudu since 1998, uncovering evidence for complex behaviours, including the earliest known use of bows and arrows.
Many of the layers featured large, 1-centimetre thick swaths of plant stems and leaves, most covering at least three square metres. The team suspected that these were the remains of bedding, but the earliest previous evidence for sleeping mats is only between 20,000 and 30,000 years old, at sites in Spain, South Africa, and Israel, where similar but more fragmentary arrangements have been found.
The swaths, which dated from 77,000 to 58,000 years ago, were made from sedges, rushes, and grasses that grow by the river. Under the microscope, the material showed signs of compression and repeated trampling. In the earliest layer the team found the leaves of Cryptocarya woodii, also known as Cape laurel, or the 'bastard camphor tree,' an aromatic plant whose leaves are used in traditional medicines even today. The leaves contain several chemical compounds that can kill insects.
Microscopic analysis also suggests that the bedding had been burned, perhaps to eliminate insect pests and get rid of accumulated garbage, so that new layers of bedding could be laid down.
Among the plant remains, Wadley's team also found tiny fragments of chipped stone and crushed, burnt bone - evidence that these were also work surfaces, where tools were fashioned and food was prepared.

Edited from Science, Popular Archaeology (8 December 2011)

Oldest rock art in Egypt discovered

Sat, 10 Dec 2011 00:20:01 +0100

Using a new technology known as optically stimulated luminescence (OSL), which can determine the time that has elapsed since buried sediment grains were last exposed to sunlight, a team of Belgian scientists and Professor John Coleman Darnell of Yale have determined that Egyptian petroglyphs found at the east bank of the Nile are about 15,000 years old, making them the oldest rock art in Egypt and possibly the earliest known graphic record in North Africa.
The rock art, situated near the modern village of Qurta, on the east bank of the Nile about 40km south of the Upper-Egyptian town of Edfu, is characterized by hammered and incised naturalistic-style images of aurochs and other wild animals. On the basis of their intrinsic characteristics, their patina and degree of weathering, as well as the archaeological and geomorphological context, these petroglyphs had been attributed to the late Pleistocene era, roughly 23,000 to 11,000 ago.
In 2008, a team of scientists discovered partly buried rock art panels at one of the sites. The deposits covering the rock art, in part composed of wind-blown sediments, were dated recently at the Laboratory of Mineralogy and Petrology of Ghent University (Belgium). This testing revealed a minimum date at least 15,000 years ago for the creation of these artworks, making them more or less contemporary with European art from the last Ice Age - such as the wall-paintings of Lascaux and Altamira caves.
How can we explain that the rock art of Qurta, executed in Egypt over about 15,000 years ago, is stylistically so similar to what we discern in Ice Age Europe at about the same time? Can one speak of direct influence or cultural exchange over such a long distance? It is not as improbable as it seems. Finds of Pleistocene rock art in southern Italy and Sicily bear analogies to the Egyptian rock art. In northern Libya, near the coast, a cave site is known with similar naturalistic images of aurochs. Considering the fact that the level of the Mediterranean Sea at the time of the last Ice Age was at least 100m lower than it is today, it cannot be excluded that Palaeolithic people established an intercontinental exchange of iconographic and symbolic concepts.
"The palaeolithic rock art at Qurta reveals that the well-known cave art of the late Pleistocene in Europe was not an isolated phenomenon. Qurta puts North Africa firmly in the world of the earliest surviving artistic tradition, and shows that tradition to have been geographically more wide-spread than heretofore imagined," commented John Darnell.

Edited from Yale News (10 November 2011), Antiquity (December 2011)

Our ancestors speak out after 3 million years

Thu, 08 Dec 2011 11:02:56 +0100

Working backward from clues in ancient skeletons, Dutch researcher Bart de Boer has built plastic models of an early hominin's vocal tract and recreated the sounds our ancestors may have made millions of years ago.
Non-human primates have an organ called an air sac - a large cavity that connects to the vocal tract - linked to an extension on the hyoid bone known as the hyoid bulla. Modern humans have neither an air sac nor an extension on the hyoid bone, but Australopithecus afarensis - a hominin species that roamed Africa approximately 3.9 million to 2.9 million years ago - had a hyoid bulla, and likely an air sac as well. De Boer built models of the human vocal tract both without an air sac, like modern humans, and with one, as Australopithecus afarensis would have had. By pushing air through the models, he could hear what various vowels sounded like.
The air sacs acted like bass drums, resonating at low frequencies, and causing vowel sounds to merge; according to Charles Harvey at New Scientist, [an Australopithecus] would have had a greatly reduced vocabulary. What, then, might our ancestors' first words have been? With air sacs, vowels tend to sound like the 'u' in 'ugg', but studies suggest it is easier to produce a consonant plus a vowel, and 'd' is easier to form with 'u'. "I think it is likely cavemen and cavewomen said 'duh' before they said 'ugg'," says de Boer.

Edited from NewScientist (23 November 2011), Discover Magazine (28 November 2011)

Paleolithic art workshop discovered in South African cave

Fri, 14 Oct 2011 10:29:17 +0100

Within the darkness of Blombos Cave near Cape Town, South Africa, archaeologists have uncovered an assemblage of tools and remains of what appears to be a workshop or work area containing toolkits used by early modern humans about 100,000 years ago to mix, make and store ochre, the earliest form of paint often used by Paleolithic people to create artwork on the walls of caves and for other decorative purposes.
"This discovery shows that humans had the conceptual ability to source, combine and store substances that were then possibly used to enhance their social practices. We believe that the manufacturing process involved the rubbing of pieces of ochre on quartzite slabs to produce a fine red powder. Ochre chips were crushed with quartz, quartzite and silcrete hammerstones/grinders and combined with heated crushed, mammal-bone, charcoal, stone chips and a liquid, which was then introduced to the abalone shells and gently stirred. A bone was probably used to stir the mixture and to transfer some of the mixture out of the shell," Professor Christopher Henshilwood from the Institute for Human Evolution at the University of the Witwatersrand, Johannesburg, said.
Henshilwood actually made the discovery while excavating the Blombos Cave along with colleagues back in 2008. Findings included an assortment of lithic hammers and grindstones, and two abalone shells that had evidently been used as containers to hold and store a red, ochre-rich mixture that was also mixed with ground bone and charcoal.
Ochre, the prime ingredient of the ancient paint, is derived from a naturally colored clay containing iron mineral oxides. It produces the yellow or red color so often associated with the ancient paint and seen to embellish drawings and other works of prehistoric art and possibly used for other purposes, such as body decoration.
The sediments in which the ochre containers were found were dated to about 100,000 years based on Optically Stimulated Luminescence (OSL) dating. The use of the ancient paint in human history is well documented only after about 60,000 years ago, which means that the Blombos Cave finds may push back the use of the paint to earlier periods.
"The recovery of these toolkits adds evidence for early technological and behavioural developments associated with humans and documents their deliberate planning, production and curation of pigmented compound and the use of containers," says Henshilwood.

Edited from Popular Archaeology (13 October 2011)

Human ancestors interbred with related species

Sat, 10 Sep 2011 11:04:24 +0100

Analysis suggests genetic mixing occurred in Africa around 35,000 years ago. According to a study published in the Proceedings of the National Academy of Sciences, up to 2 percent of the genomes of some modern African populations may originally come from a closely related species.
Palaeontologists have long wondered whether modern humans came from a single, isolated population or a mix of various species. Last year, an analysis comparing the Neanderthal genome sequence to that of modern Homo sapiens showed that some interbreeding did take place between the two species in Europe some time between 80,000 and 30,000 years ago.
It has been a mystery whether similar mixing took place among Homo species even earlier, before the populations that became modern humans left Africa. To find out, evolutionary biologist Michael Hammer at the University of Arizona in Tucson (USA) and his colleagues studied DNA from two African hunter-gatherer groups, the Biaka Pygmies and the San, as well as from a West African agricultural population known as the Mandenka.
Each of these groups is descended from populations that are thought to have remained in Africa, meaning they would have avoided the genetic bottleneck effect that usually occurs with migration. This means the groups show particularly high genetic diversity, which makes their genomes more likely to have retained evidence of ancient genetic mixing.
Because direct comparison to archaic specimens wasn't possible, the authors used computer models to simulate how infiltration from different populations might have affected patterns of variation within modern genomes. On chromosomes 4, 13 and 18, the researchers found genetic regions that were more divergent on average than known modern sequences at the same locations, hinting at a different origin. Hammer and his colleagues say these sequences must have come from a now-extinct member of the Homo genus that broke away from the modern human lineage around 700,000 years ago.
Hammer says this disproves the conventional view that we are descended from a single population that arose in Africa and replaced all other Homo species without interbreeding. "We need to modify the standard model of human origins," he concluded.

Edited from Nature News, Popular Archaeology, EurekAlert! (5 September 2011)

The first advanced stone tool?

Fri, 09 Sep 2011 10:25:42 +0100

Whilst the first stone tools to have been found so far are recorded to be the 'Oldowan Tools' (named after the gorge in Tanzania where they were first found), dating from approximately 2.6 million years ago, they were very crude and were used simply for hacking and crushing.
Until recently it was believed that the oldest 'advanced' stone tools were from Ethiopia and dating from approximately 1.4 million years ago. These tools were far more sophisticated and were chipped into shape to allow more delicate cutting and scraping techniques, as well as the previous crushing attributes.
But now that boundary has been pushed back to approximately 1.76 million years ago by a find on the shores of Lake Turkana, in Kenya. These finds belong to a group known as 'Acheulian Tools', named after a high profile site in France. This is where the story gets both interesting and confusing. Acheulian tools have been generally found on sites also containing the fossilised bones of Homo Erectus and it was believed that they were developed from the cruder Oldowan tools as Homo Erectus advanced and became more skillful.
However, on a contemporary site (dating from 1.8 million years ago) in Georgia, Asia, only Oldowan tools were found alongside the Homo Erectus remains. This could have two possible meanings. The first is that Homo Erectus (or a predecessor) migrated from Africa to Asia earlier and either never developed the advanced skills or individuals who had the skills died out before passing them on. The second theory is more radical and proposes that Homo Erectus began in Asia and migrated to Africa! Both these suppositions need more evidence before one or the other can be confirmed.

Edited from guardian.co.uk (31 August 2011)

Ancient Saharan brain surgery

Thu, 25 Aug 2011 17:48:35 +0100

Skulls of three men from North Africa's ancient Garamantian civilisation, which flourished in the Sahara Desert from 3,100 to 1,400 years ago, contain holes and indentations that were made intentionally to treat wounds or for other medical reasons, say anthropologist Efthymia Nikita of the University of Cambridge in England and her colleagues.
Signs of renewed bone growth around the rims of these cranial openings indicate that the men, who lived roughly 2,000 years ago, survived the procedures. Given the evidence of widespread trade networks in North Africa several thousand years ago, "the knowledge of cranial surgical techniques must have been among the cultural traits that spread among populations," Nikita says.
Previously excavated North African sites contain the earliest evidence of scraping, cutting or drilling pieces of bone out of people's skulls, a practice known as trepanation. Skull surgery occurred as early as 13,000 years ago in what is now Morocco. Ancient Egyptians performed the technique starting around 4,000 years ago, as did pre-Inca groups living in South America 1,000 years ago. Some modern North African populations have used trepanation to treat headaches following injuries or disease.

Edited from ScienceNews (17 August 2011)

The Nok - West Africa's earliest known civilisation

Mon, 15 Aug 2011 08:57:24 +0100

In 1943, in the central Nigerian town of Jos, British archaeologist Bernard Fagg received a terracotta head that had been on a scarecrow in a nearby field. The piece resembled a terracotta monkey head he had seen a few years earlier, and neither piece matched the artefacts of any known ancient African civilisation.
Fagg discovered local people had been finding terracottas in odd places for years. He soon gathered nearly 200. Soil analysis dated them to around 500 BCE. This seemed impossible since the type of complex societies that would have produced such works were not supposed to have existed in West Africa that early. But when Fagg subjected plant matter found embedded in the terracotta to the then-new technique of radiocarbon dating, the dates ranged from 440 BCE to 200 CE. He later dated the Jemaa scarecrow head to about 500 BCE using thermo-luminescence, which gauges the time since baked clay was fired. Fagg and his collaborators had apparently discovered a hitherto unknown civilisation, which he named Nok.
Fagg also unexpectedly found 13 iron furnaces, with terracotta figurines in such close association that he postulated they were objects of worship to aid blacksmithing and smelting. Carbon dating gave the Nok the earliest dates for iron smelting in sub-Saharan Africa up to that time.
Fagg knew such a society did not appear in isolation. He later wrote that Nok culture had almost certainly begun earlier and survived longer than he had evidence for at the time. Scholars are now finding that Nok may have been the first complex civilisation in West Africa, existing from at least 900 BCE to about 200 CE, and their terracottas have become some of the most iconic ancient objects from Africa.
Excavators regularly find iron tools only a short distance from Nok stone axes, suggesting they were used in the same communities - maybe even the same households - attesting to the manufacture of iron while stone was still being used.
Evidence has also reinforced a view held by most archaeologists that ancient West Africans moved from stone tools directly to iron, without an intervening copper age. That's a leap that few other parts of the world appear to have made. With the exception of a site in Mauritania known as Grotte aux Chauves-souris, and another in Niger called Cuivre II, researchers have yet to find evidence of copper smelting before iron smelting anywhere in West Africa.

Edited from Archaeology (July/August 2011)

Final journey for 8,000-year-old African canoe

Sat, 13 Aug 2011 10:15:13 +0100

A precious artifact, known as the Dufuna Canoe, is to be permanently housed in a new museum complex, located in Damaturu, the Yobe State capital, in Nigeria. The canoe is perported to be the oldest in Africa and the third oldest in the world. It was found by accident, nearly 25 years ago, by a cattle farmer when digging a well.
The canoe is dated at approximately 6,000 BCE and is 8.4 metres long and double ended. It is being prepared for its exhibition by the Nigerian National Commission for Museums and Monuments, together with a team from the University of Frankfurt, Germany and the Centre for Transaharan Studies, University of Maiduguri, Nigeria.

Edited from All africa.com (5 August 2011)

An early understanding of tides

Sat, 06 Aug 2011 16:09:47 +0100

Those of you who live near the sea or the ocean will understand the importance of knowing your local tide timetable, with most of us using a booklet listing the low and high tides. But imagine yourself in the Stone Age, how would you cope? It has long been thought that our human ancestors did not develop complex and abstract thought processes until approximately 50,000 years ago. An archaeologist from Arizona State University (USA), Curtis Marean, is about to blow that theory apart. His team have been working in caves along the southern coastline of South Africa, in an area known as Pinnacle Point, with astounding results.
Their work had initially centred around a cave which had shown signs of occupation from approximately 162,000 BCE. At that time the sea levels were lower and the cave would have been between two and five kilometrers from the waters edge. Evidence of shellfish, such as brown mussels and sea snails have been found in the cave, dated at approximately 162,000 BCE, together with limpets ans sand mussels dated around 108,000 BCE, most of which could only have been harvested at some of the lowest tides, leading to the conclusion that these early fishermen had a rudimentary knowledge of the phases of the moon.
The early harvesting of these shellfish would have had a cumulative effect on the development of these early cave dwellers as they were protein rish and high in omega-3 fatty acids, well known as a vital ingredient for brain development. Curtis Marean goes one step further and believes that they progressed from living and eating for the day to harvesting shellfish for storage. Extrapolating this theory further, it may have given the edge to those early Homo Sapiens when they first migrated to Europe and met the Neanderthals. Evidence shows that early Homo Sapiens caves around the fringes of the Mediterranean Sea contain the remains of shellfish, whereas Neanderthal caves do not, suggesting they still lived for the day and were not able to plan where the next meal came from.
Curtis Marean and his team are a long way from proving their hypothesis and they have now expanded their investigations to the eastern coast.

Edited from ScienceNews (13 August 2011)

Part ape, part human

Thu, 28 Jul 2011 10:03:32 +0100

The eroded limestone cave called Malapa - about 40km (25 miles) northwest of Johannesburg - is in a region famous for its ancient human fossils. Paleo-anthropologist Lee Berger believes Malapa may hold the key to the origin of the first species enough like us to be called human - Australopithecus sediba.
The evidence includes an australopith's little brain (with some curiously modern features), apelike shoulders and arms adapted to climbing in trees, attached to a bizarrely modern hand with the precision grip of a toolmaker. According to the researchers, a adult female's foot presents an even odder melange; her mostly modern ankle is connected to a heel bone more primitive than that of A. afarensis - Lucy's species - which is at least a million years older.
Two million years ago, a cave-studded aquifer lay beneath an undulating plain of shallow, wooded valleys and rolling hills. Some of the caves were open to the surface through steep entryways or vertical shafts stretching up to 50 metres (160 feet).
In wet periods, animals could easily drink from seepage ponds near the surface. During drier times they would risk a plunge down a hidden shaft. After death, their bodies would rapidly become entombed in a single, thick layer of sand and clay - preserving the skeletons, right down to tiny bones of the hands and feet.
The brain of A. sediba is a chimp-like 420 cubic centimetres - not at all unusual for something called Australopithecus. The shape, however, is. "The frontal lobes... appear to be different sizes," notes paleo-anthropologist Kristian Carlson. Pronounced asymmetry between right and left brain hemispheres is a hallmark of humans, because our cerebrum has become specialised, with the left side more involved in language.
Anatomically, the species shows a mix of primitive and advanced traits. The long legs and modern ankle are key elements on the human side, as is the surprisingly human-like pelvis built for a fully bipedal stride, smaller teeth and chewing muscles, a projecting nose and some other features of the face, and that remarkable precision-grip hand. These traits are enough for the team to propose it as the species most likely to have given rise to Homo.

Edited from National Geographic (August 2011)

Populations intermixed well after migration out of Africa

Fri, 22 Jul 2011 09:48:07 +0100

Researchers looking into human evolution have developed a new technique to study more intricately the movement of humans from Africa. The study, conducted by the Wellcome Trust Sanger Institute has found that African and non-African populations continued to to exchange genetic materical well after migration out of Africa 60,000 years ago. Four male genomes were sequenced and compared: one each from China, Europe, Korea and West Africa respectively.
"Previous methods to explore these questions using genetic data have looked at a subset of the human genome. Our new approach uses the whole sequence of single individuals, and relies on fewer assumptions. Using such techniques we will be able to capitalize on the revolution in genome sequencing and analysis from projects such as The 1000 Genomes Project, and, as more people are sequenced, build a progressively finer detail picture of human genetic history," said Dr Richard Durbin, joint head of Human Genetics and leader of the Genome Informatics Group at the Sanger Institute.
The researchers discovered that although African and non-African populations began to differentiate as early as 100,000-120,000 years ago, they remained largely as one population until 60-80,000 years ago. Following on from this time the population of European and East Asian ancestors dropped to one-tenth of its earlier size, overlapping the period during which modern human fossils and artefacts appear across Europe and Asia.
"This elegant tool provides opportunities for further research to enable us to learn more about population history," says co-author Heng Li, from the Sanger Institute. "Each human genome contains information from the mother and the father, and the differences between these at any place in the genome carry information about its history. Since the genome sequence is so large, we can combine the information from tens of thousands of different places in the genome to build up a composite history of the ancestral contributions to the particular individual who was sequenced."

Edited from ScienceDaily (13 July 2011)

Ethiopian lake sediments reveal history of African droughts

Tue, 19 Jul 2011 08:25:49 +0100

A new survey of Lake Tana in Ethiopia - the source of the Blue Nile - suggests that drought may have contributed to the demise of the ancient Egyptian 'Old Kingdom', around 4200 years ago. A team led by the University of Aberystwyth (Wales) used seismic surveys and sediment cores to work out how the lake's water level has varied over the past 17,000 years and linked this to evidence for global climate change.
Understanding how and why rainfall patterns change is particularly important for sub-Saharan Africa, where prolonged droughts have such serious social and economic consequences. The climate here is dominated by the African-Asian monsoon and the movements of the Inter-Tropical Convergence Zone (ITCZ) - an area of erratic weather patterns, where winds from the northern and southern hemispheres meet close to the equator. Sailors know it as the Doldrums.
Seasonal movements of the zone can affect the strength of the monsoon, and be traced in ancient lake sediments. Lake Tana is particularly good for this kind of research because it's close to the northern limit of the zone, so even slight a southward movement of the zone is reflected in the lake's geological history.
"Finding a distinct dry period around the time of decline of the Old Kingdom is complicated by the fact that the climate was becoming drier overall during that time anyway," explains Dr Michael Marshall, of Aberystwyth University.
Nevertheless, the researchers' analysis of the sediments did reveal a distinct dry episode around 4200 years ago. This would have lowered water levels in Lake Tana and reduced the flow of the Nile, interrupting the regular supply of fertile sediment to the Nile delta. Archaeological evidence shows that the Old Kingdom was already beginning to wane; reduced Nile flow could have contributed to its demise.

Edited from PhysOrg (12 July 2011)

Archeological findings reveal central African history

Sun, 10 Jul 2011 09:41:12 +0100

In late May, scores of researchers from around the world converged on the Cameroonian capital, Yaounde, for the International Conference on Rescue Archeology. At the meeting, archaeologists introduced the new findings in a book titled: "Kome-Kribi: Rescue Archeology Along the Chad-Cameroon Oil Pipeline; 1999-2004".
Archaeologists say the findings mark a breakthrough that requires a rewriting of the history of Cameroon and the rest of Central Africa. Artefacts from hundreds of archaeological sites from southern Chad to the shores of the Atlantic Ocean in Cameroon have turned up several surprises.
According to Professor Scott MacEachern, a specialist in African Archaeology at Bowdoin College in Brunswick, Maine (USA), 472 archaeological sites were found along the more than 1000 kilometre-long pipeline in both Cameroon and Chad - some dating back 100,000 years. The researchers have urged governments in Central Africa to use the new documents to rewrite regional history.
Officials at Cameroon's Ministry of Culture pledge to act on recommendations of the archeologists - including the creation of a national commission on cultural heritage, which would work to avoid the destruction of archeological sites during major infrastructure projects, the construction of a national museum, and the strengthening of laws on the conservation of cultural artefacts.
Raymond Asombang, lecturer in the Department of Archeology at the University of Yaounde, says: "We need to know that in civilisation, you are only adding your own contribution to the contributions of other people. So when we see what our ancestors have done, we will know what our contribution to that civilisation will be."

Edited from VOA News (6 July 2011)