Introduction:
Of all early humans, none have captured the public imagination to anywhere near the extent of the Neanderthals. Indeed, with the possible exception of the dinosaurs, no extinct species is so deeply rooted in our popular culture. The idea that tens of thousands of years ago, people very much like ourselves shared the planet with another human species is one that intrigues many.
Although like “dinosaur”, the term “Neanderthal” is all-too-often used in a pejorative sense, in literature Neanderthals have generally been portrayed in a sympathetic light, for example The Inheritors by William Golding; Jean M. Auel’s Clan of the Cave Bear series; and The Ugly Little Boy by Isaac Asimov. The Neanderthal Parallax is an award-winning trilogy by Canadian SF writer Bob Sawyer about a team of scientists who accidentally make contact with a parallel universe in which the Neanderthals rather than Homo sapiens became the dominant life form on Earth.
Once thought of as a subspecies of Homo sapiens, genetic evidence now suggests that Neanderthals diverged from modern humans long before either species existed. Green et al (2006) give a date of 500,000 years ago. “Classic” Neanderthals emerged in Europe around 200,000 years ago (Cameron & Groves, 2004), by which time modern humans were emerging in Africa.
Etymology:
The term Neanderthal comes from Neander Thal (Neander Valley), near Dusseldorf, where the type specimen Neanderthal 1 was discovered at Feldhofer Cave in 1856. The German spelling was changed to Neander Tal in 1901, hence the commonly-used variant spelling Neandertal; however this usage is not acceptable for the scientific name Homo neanderthalensis, which was assigned before the change in spelling. Under rules of taxonomic nomenclature, once a name has been assigned, it cannot be changed.
The Neander Valley is named for Joachim Neumann, a 17th Century theologian who is usually referred to by the classicised form of his surname, Neander. He is best known for the hymn Praise to The Lord, The Almighty, the King of Creation.
The literal meaning of Neanderthal is therefore, rather ironically, New Man’s Valley.
Discovery:
Though the first fossil recognised as not representing a modern human Neanderthal 1 was not actually the first discovery of a Neanderthal. Specimens had previously been recovered in Ennis Cave, Belgium between 1829 and 1830 and Forbes Cave, Gibraltar in 1848; however their significance was not immediately recognised.
The Feldshofer Cave discovery comprises a skullcap and two femora, three bones from the right arm, two from the left arm, part of the left ilium, fragments of a scapula, and ribs. They were recovered by quarry workers in 1856. Unfortunately they may have inadvertently discarded further remains and other items that could well have included tools, and there is almost no record of context and associations (Klein, 1999). The find was examined by a local schoolteacher and amateur naturalist, Johann Karl Fuhlrott, who noted that the remains were unlike those of modern humans. Fuhlrott passed the remains on to Hermann Schaaffhausen, Professor of Anatomy at the University of Bonn. The pair jointly announced the discovery in 1857. However Schaaffhausen considered the Neanderthals to represent an ancient Northern European race predating the Germans and the Celts. That they might represent a new species of human was first suggested in 1864 by the Irish anatomist William King, who proposed the name Homo neanderthalensis. King’s suggestion was not widely accepted at first and, foreshadowing the debate over the Flores hominins almost a century and a half later, the Prussian pathologist Rudolf Virchow dismissed the Feldshofer remains as belonging to a modern human affected by disease.
Neanderthal 1 is now believed to be 40,000 years old (Scarre, 2005).
Key sites:
The Neanderthals are known from numerous sites in Eurasia ranging from the United Kingdom to the northwest, Uzbekistan to the east, Israel to the south, and Gibraltar to the southwest. These include:
Krapina, near Zagreb, Croatia. 120,000 years old. This large find comprises roughly 900 fragmentary remains representing from between 14 to as many as 82 individuals, discovered by Dragutin Gorjanović-Kramberger between 1899 and 1905.
La Chapelle-aux-Saints, France. La Chapelle-aux-Saints 1 is a partial skeleton, 50,000 - 60,000 years old.
Le Moustier, France. c. 40,000 years old. Le Moustier 1 young adult (partial skeleton); Le Moustier 2 child (partial skeleton). The Mousterian tool tradition, associated with the Neanderthals, is named for tools found at this site.
Kebara Cave, Mt Carmel, Israel. In 1983 an adult male skeleton (Kebara 2) was found. It is 50,000 - 55,000 years old and includes the most complete pelvis so far found. Kebara 1, an adult male, is also of significance, having provided the only known hyoid bone of a pre-modern human.
Tabun Cave, Mt Carmel, Israel. Tabun-C 1 is the almost complete 120,000 years skeleton of a Neanderthal woman.
Physical description:
The Neanderthal braincase is long and relatively low and is cylindrical when viewed from behind. The cranial capacity is between 1245-1740cc, averaging 1520cc, compared with 1560cc for an early modern human, or 1340cc for a present-day human. The frontal bone is low and receding, with continuous brow-ridges forming a double arch above the orbits. The face is long and prognathous and the chin is usually absent, with the cheekbones sloping backwards. The nasal aperture is broad, high and prominent.
Postcranial bones are robust and stout, the vertebral column heavily built, the ribcage large and wide, a long clavicle, large shoulder and elbow joints, short forearm, hands with strong grip and wide finger-tips, wide pelvis, longer and thinner pubis, thick-walled femur, short and thick-walled tibia, large ankle-joints and wide, strong toe bones. There are well-developed muscle markings throughout.
Neanderthals were 12 to 14 cm (4½-5½ in) shorter than modern humans. Based on 45 long bones from (at most) 14 males and 7 females, Neanderthal males averaged between 164 to 168 cm (5 ft 4½ in to 5 ft 6 in) and females 152 to 156 cm (5 ft to 5 ft 1½) tall (Helmuth, 1998). Their body weight has been estimated at 75kg on average, comparable to that of present-day humans (Cameron & Groves, 2004; Conroy, 1997; Klein, 1999).
To sum up, Neanderthals were powerfully built, far more so than early modern humans, even though the latter were more robust than present-day humans. As Conroy (1997) points out, Neanderthals probably didn’t do limp-wristed hand-shakes!
Adaptations of the Neanderthals:
The limb proportions of the Neanderthals were probably adaptations to living in cold places, and are mirrored to some extent by those of present-day Inuit and Sami people. The Neanderthals were however more extreme in their limb proportions, despite probably living in more moderate conditions. This suggests they were more reliant on their physiology to combat the cold than any modern human (Klein, 1999).
The robust (thick-walled) limbs and large bodies suggest physical stress was a part of their everyday life. (Scarre, 2005). The upper limbs may have been adapted to heavy foraging such as spear thrusting while the lower limbs are those of long-range bipeds (Cameron & Groves, 2004).
The large nasal aperture and sinus tracts may have been maximised to warm and moisten the dry, cold tundra air (Scarre, 2005).
Facial development and powerful jaws may have reflected the use of teeth as a vice-like tool, possibly for gripping mammal hides while skinning them with stone tools. Wear on teeth consistent with this hypothesis (Cameron & Groves, 2004; Scarre, 2005).
It has been suggested that many distinctive Neanderthal features resulted from genetic drift (random change) in a population that was isolated in Europe for much of its history, rather than the traditional explanation of natural selection. This is suggested by the way Neanderthal-like features seem to have accreted in pre-Neanderthal hominins and supported by a recent study, which obtained the divergence time for Neanderthals from modern humans based on statistical comparisons of cranial metrics and obtained a mean figure of 373,000 years, close to figures based on comparisons of DNA sequences. This implies that the cranial and DNA sequence data largely reflects neutral mutational divergence, causing it to track population history rather than the effects of natural selection (Weaver et al, 2008).
Gestation period of the Neanderthals:
In 1984, Erik Trinkaus noticed that the superior pubic ramus of the Neanderthal pelvis seemed to be longer than that of a modern human, indicating a wider birth canal. This he claimed implied that the gestation period of Neanderthals was longer than that of modern humans, possibly as long as a year (Trinkaus, 1984). Other theories were proposed to explain the difference: that it simply reflected the greater size of the head in comparison to the relatively short stature (Rosenberg, 1985); or that the brain grew faster in utero compared with modern humans (Dean et al, 1986).
In 1987 an analysis of the Kebara 2 pelvis was published (Rak & Arensburg, 1987) which showed that the pelvic inlet was comparable to that of a modern human and that the length of the superior pubic ramus was due to a more externally rotated hip bone. This suggested that the unique features of the Neanderthal pelvis might be due to locomotion and posture-related biomechanics rather than the need for an enlarged birth canal.
Neanderthals skin and hair colour:
A study has recently been carried out of the melanocortin 1 receptor (mc1r) gene in Neanderthals. This gene is responsible for skin and hair colour variation in humans. Variants of mc1r with reduced function give rise to pale skin and red hair. DNA was extracted from two Neanderthal fossils, Monti Lessini (Italy) and El Sidrón 1252 (Spain). A mutation of the gene, known as R307G, was found. This mutation is not present in modern humans. The gene was then expressed in COS-7 cells (a cell culture derived from vervet monkeys often used in biomolecular research). The results suggested that the R307G allele had reduced function. This does not confirm that the two individuals tested – much less all Neanderthals – had red hair and pale skin, but it is more likely if they were homozygous or compound heterozygous for this allele. Whether this was the case for these two Neanderthals was not determined by the study (Lalueza-Fox et al, 2007).
Evolutionary history:
It is now generally accepted that the Neanderthals were a separate species to Homo sapiens and not a subspecies; nor does it now seem likely that modern Europeans are descended from Neanderthals. Rather it would appear that the two lineages diverged around 500,000 years ago (based on genetic evidence) or possibly later, around 370,000 years ago (based on cranial data).
In a 2002 study, Yoel Rak of the Tel Aviv University demonstrated that the specialized Neanderthal mandibular ramus (lower jawbone) morphology is an element in a complex of derived morphologies of the mandible and face that are unique to the Neanderthals and the corresponding features in modern humans are actually primitive retentions from Homo erectus. This provides further support for the contention that Neanderthals are not ancestral to modern humans (Rak et al, 2002).
Homo antecessor, known from the Atapuerca Hills of northern Spain, has been touted as a possible ancestor. These hominins lived 700,000 – 800,000 years ago, but even assuming it is a valid species at all it seems more likely to have been an offshoot of Homo ergaster that died off without issue, possibly during the glacial periods of 600,000 – 800,000 years ago.
The probable common ancestor is Homo heidelbergensis. Neanderthal-like features seem to have accreted in the European deme of this species; for example the Steinheim skull from Stuttgart, Germany; the Sima de los Huesos specimens from Atapuerca in northern Spain and the Swanscombe cranium from the UK.
Cameron & Groves (2004) cautiously accept these hominins as a distinct species, Homo steinheimensis, but argue that they are really primitive Neanderthals. At all events they are clearly intermediate between Homo heidelbergensis and “classic” Neanderthals. “Incipient Neanderthal features” include the configuration of the supraorbital tori, the large size of the nasal openings, the medial projection from the side walls of the nasal cavity, developed occipital torus and suprainiac depression and a long cranium with a slightly more elevated frontal bone (Cameron & Groves, 2004).
Not all these features are seen in every specimen; different features appeared at different times in different populations. Some are more Neanderthal-like in the face; others in the braincase. This does suggest that the distinctive Neanderthal craniofacial complex evolved as a series of disconnected features, in turn supporting the view that Neanderthal morphology was more a product of a series of neutral mutations (genetic drift) than natural selection (see above).
The “classic” Neanderthals had emerged in Europe by 200,000 years ago. The Neanderthals from Western Asia and the Levant were probably an expansion of the European population.
The Mousterian industry:
The Neanderthals are generally associated with the Mode 3 Technology or Mousterian industry, named for the type site, Le Moustier, a rock shelter in the Dordogne region in the south of France. However this technology is also associated with early modern humans; conversely later Neanderthals have been associated with more advanced tool kits.
The Mousterian tools are considerably more sophisticated than those employed by either Homo heidelbergensis or the “ante-Neanderthal” Homo steinheimensis. The Mousterian industry is basically a stone core technology in which the core is pre-shaped to facilitate the striking off of flakes of a desired shape, which in turn can be retouched to provide a continuous cutting edge.
The pre-shaped cores are known as Levallois cores, after a site at Levallois-Perret, in the north-western suburbs of Paris, where examples have been known since the 19th Century. A number of Levallois flaking techniques appear to have been employed, allowing a degree of control to be exercised over the shape and size of the resulting flakes. The tools were fashioned for specific purposes, unlike the preceding Acheulian multi-purpose artefacts. Considerable planning, involving at least six separate stages, went into their production. The lithic technology of the Neanderthals appears have been very flexible, with different solutions reflecting the size, shape and quality of available materials.
In the 1950s and early 1960s, François Bordes (1919-1981), a leading figure in French Palaeolithic archaeology, formalised a typology that recognised a total of 63 different tool types in three classes: sidescrapers, retouched points and denticulates (toothed pieces). A sidescraper was defined as a flake on which one or more edges bear smooth, continuous retouch; a point as a flake on which two continuously-retouched edges converged directly opposite the butt; and a denticulate as flake that was retouched to produce a toothed edge. A denticulate with only one indentation was designated a notch.
In addition, the overall Mousterian was divided into five groups or facies: the Mousterian of Acheulian Tradition (MAT) A and B, Typical Mousterian, Denticulate Mousterian and Charentian. The groups were assigned on the basis of varying frequency of tool types such as hand axes, scrapers, points, etc. Thus MAT A & B were characterised by abundant hand-axes, which are rare or absent in the other groups; Typical Mousterian was dominated by sidescrapers; Denticulate Mousterian by denticulates and notches, etc.
Bordes believed that his five groups were cultural in nature, representing different contemporary ethnic groups or tribes in Middle Palaeolithic society.
That Bordes’ scheme represents the reality of the Mousterian industry is questionable as tool types often grade into one another and may well represent re-sharpening of a smaller number of basic forms – i.e. what Bordes saw as several distinct types may represent a single tool type at different stages of its life before being finally discarded. The extent to which tools were refurbished during their life would in turn have depended on the quality of available raw materials; if these were scarce, existing tools would have had to be retained longer. Also if a particular site remained in use for a long time, its occupants appear to have been more prone to re-use and modify the tools already at hand.
In addition, some assemblages excavated after Bordes defined his facies clearly fall between the variants as proposed, suggesting that inter-assemblage variation is continuous rather than discreet. Lewis and Sally Binford have suggested that this variation was functional and related to the performance of various tasks. For them, the differing assemblages simply reflected differing tasks carried out by the same people, either at different sites, or at the same site at different times, possibly different seasons.
Finally it is now clear that the use to which the Mousterian stone artefacts were actually put does not in general correspond to the names assigned to them. Microwear analysis suggests that while the denticulates and notches were largely used to work wood, the sidescrapers and points were used to work a greater variety of materials including wood, meat, bone and animal hide. The latter show evidence of hafting to wooden handles and – though only in the case of points recovered from sites in Israel – to wooden spear shafts.
The Châtelperronian industry:
The Châtelperronian industry, known from central and south western France and Northern Spain also appears to be associated with the Neanderthals, whose remains rather than those of modern humans have been found at sites such as the Grotte du Renne at Arcy-sur-Cure and Saint Césaire. The industry is named for the type site of la Grotte des Fées, in Châtelperron, Allier, France and probably began around 45,000 years ago, persisting until 36,000 years ago. The stone artefact assemblages generally combine typical Mousterian stone tools with articles more typical of the Upper Palaeolithic such as endscrapers and burins, bone tools and personal ornaments. At the Arcy site, Châtelperronian articles included bone implements that appeared to have been decorated and animal teeth, pieces of ivory, bone and shells that were pierced or grooved for use as beads or pendants. Furthermore the living space has been modified to an extent common only in the Upper Palaeolithic, with traces of hut emplacements including a circle of 11 postholes possibly supporting mammoth tusks and enclosing an area of 3 to 4 sq. metres, which was paved with limestone plaques.
The Châtelperronian people, in short, show evidence of modern human behaviour, but whether this was of independent Neanderthal origin or simply borrowed from neighbouring Cro-Magnon (i.e. modern) humans associated with the Aurignacian culture remains contentious. João Zilhão, Francesco d’Errico argue for independent origin (Zilhão et al, 2006) but Richard Klein claims that the most persuasive Upper Palaeolithic elements of the Châtelperronian only appear towards its end, suggesting acculturisation from the Cro-Magnon people (Klein & Edgar, 2002). Steven Mithen has stated that the coincidence of the Neanderthals coming up with the use of beads just before modern humans appeared wearing them is “just too great to be believed” (Mithen, 2005).
Burials:
It is widely believed that the Neanderthals intentionally buried their dead, with evidence of Neanderthal burials known from Shanidar Cave in northern Iraq and from a number of sites in France.
The Shanidar site was excavated between 1953 and 1960 by Ralph Solecki, who recovered the remains of nine Neanderthal individuals comprising two groups. One group dated to around 60,000 years ago and the other to 70,000 – 80,000 years ago. Some individuals appeared to have been killed by a cave-in, but others had been intentionally buried. One individual, Shanidar 4 was supposedly found in association with pollen, suggesting flowers had been used in the burial, but the pollen could well be contamination introduced during the excavation of the site.
Another individual, Shanidar 1, an elderly male victim of the cave-in, showed evidence of numerous injuries. That bone-healing had occurred implied that they had been sustained before his death. In turn, this suggests that other members of his group must have cared for him during periods of convalescence.
In France, burials are known at La Chapelle-aux-Saints (another elderly male, see above); Le Moustier (a young adult, see above); Regourdou (one individual in a stone-lined pit) and La Ferrassie. The latter site appears to be a Neanderthal cemetery in which seven individuals had been buried. There were two adults and five children, suggesting a family plot. The site may be 70,000 years old.
Although none of these sites show conclusive evidence of grave goods, the purpose of the burials must have been more than simply disposing of dead bodies, as there are far simpler ways of achieving this. Even if the Neanderthals lacked symbolic behaviour, in my view there is no reason to suppose that they felt the loss of kin or friends any less keenly than do modern people.
Settlements:
Neanderthal patterns of land use differ from those of bother earlier and modern humans. Site usage is well-documented from France and Spain. In south-western France, cave and rock shelter sites share certain features:
1. Well-sheltered locations in positions offering extensive and wide-ranging views over ecologically-diverse adjacent valley habitats.
2. Easy access to abundant and high-quality raw materials.
3. Sites located to serve as central places from which diverse economic and technical activities could be connected.
Open-air sites are typically located on higher, more exposed locations, usually on major plateaus, close to springs, streams or lakes (Cameron & Groves, 2004).
The caves and rock shelters were probably living places rather than places for killing animals and butchery. Stacked hearths evidence repeated fire building over thousands of years. The fires would have been used for cooking food and to provide warmth, light and protection from predators. Though some hearths were underlain by rocks, they are generally fairly unsophisticated. A similar pattern is seen at African Middle Stone Age sites, which were occupied by early modern humans. There is a sharp contrast with the later hearths of modern humans in the Upper Palaeolithic. These were fitted with stone liners, air-intake ditches and other features to control airflow and heat dissipation.
The open-air sites are harder to interpret. Some are near sources of stone raw materials and have extensive flaking debris – clearly these sites were used as stone tool workshops. But generally preservation of the evidence at these sites has not been sufficient to distinguish between possible usage as campsites or as killing and butchery sites.
Generally these sites and the contemporary MSA sites in Africa show very little signs of modification, other than hearths. This is again in contrast to the extensive architecture seen at later Upper Palaeolithic sites, which include stone walls, pavements and pits.
It has been shown that where stone sources at Neanderthal and African MSA sites have been established, they have turned out to be largely local, with less than 5% having come from more than 30km away. Again, there is a sharp contrast with the Upper Palaeolithic, where evidence exists of around 20-25% of stone having been obtained from distances greater than 30km.
The inferences are that in the Upper Palaeolithic, modern humans controlled larger territories than either their earlier brethren in Africa or the Neanderthals; or that they had more extensive trade networks than either of these. (Klein 1999).
Food-gathering strategies:
Isotopic analysis of Neanderthal bones suggests that up to 90% of their protein intake came from meat. Some of this may have been scavenged, but there is evidence for the hunting of medium sized and even large carnivores. A wooden spear with a fire-hardened tip was found lodged between the ribs of a mammoth at a 130,000 year old site in Germany. At La Cotte de St. Brelade, a cave site in Jersey (then part of mainland Europe), there is evidence of mass slaughter, where animals were stampeded over the edge of cliffs, butchered and dragged into the cave for consumption. The Neanderthals also ate any available small animals including tortoises, turtles, rabbits and shellfish (Cameron & Groves, 2004; Scarre, 2005).
Language and Behavioural modernity:
Anthropologists define modern human behaviour as the use of abstract thought, symbolic behaviour (such as art and creative expression), use of syntactically-complex language and the ability to plan ahead.
The following are generally accepted as evidence of modern human behaviour:
1. Finely made tools.
2. Fishing.
3. Evidence of long-distance trade among groups.
4. Use of pigment and jewellery for decoration or self-ornamentation.
5. Figurative art, such as cave paintings, petroglyphs and figurines.
6. Burial of the dead.
7. Systematic use of space in living-areas, with particular areas reserved for particular functions, e.g. food storage.
There are two main views for the origins of modern human behaviour. The ‘‘Great Leap Forward” model attributes the sudden appearance of symbolic artefacts to a “big bang” of human consciousness triggered by a genetic mutation, 50,000 years ago, long after the appearance of the first anatomically-modern humans, who may have lived as long as 195,000 years ago (Omo Kibish 1 and 2, Ethiopia) or at least 154,000-160,000 years ago (Herto Bouri, Ethiopia). On this model, modern human behaviour is restricted to anatomically modern humans who lived after 50,000 years ago. This view is supported by many authorities including Jared Diamond, Steven Mithen and Richard Klein (see Diamond, 1991; Mithen, 1996 & 2005; Klein & Edgar, 2002).
A key question is did Neanderthals possess the same linguistic abilities as modern humans. As noted above, this is crucial to the question of their behavioural modernity. The hyoid bone from the Kebara I skeleton (see above) is more-or-less identical to that of a modern human. The hyoid bone is attached to the cartilage in the larynx and anchors the muscles required for speech. The Neanderthal larynx itself is now believed to be positioned low in the throat, like that of a modern human. Earlier claims that the Neanderthal larynx was positioned high in the throat, like a chimpanzee (or a modern human baby) are now known to be incorrect; they were based on the Neanderthal specimen from La Chapelle-aux-Saints, which is now known to be too badly distorted and incomplete for a proper reconstruction.
The hyperglossal canal, which carries nerves from the brain to the tongue, is the same width as that of modern humans, suggesting the same degree of enervation; but those of earlier hominins are more comparable to those of present-day apes. Also comparable is the nerve-carrying canal controlling the diaphragm and hence breathing. While this latter feature could relate to running, etc, it can also be used to provide the level of fine breathing control required for speech.
All in all, then, the Neanderthals appear to have had all the anatomical features required for speech. But did they possess the cognitive ability to handle syntactically-complex language?
No, says Richard Klein, a leading proponent of the Great Leap Forward theory. Klein’s original “prime suspect” for the genetic mutation leading to modern human behaviour was a gene known as FOXP2, or forkhead box P2, which regulates a number of other genes, some of which are believed to play a role in the development of the parts of the brain associated with speech, although the exact genes involved are not known. The FOXP2 gene is not unique to humans, but exists with very few differences in other animals.
The first clue that FOXP2 might be a “speech gene” came from studies of Family KE, an extended British family living in London (their actual identity is not in the public domain). Some members of the family have problems with aspects of grammar, including the use of inflexions for marking tense. They also have difficulty in producing the fine movements of the tongue and lips required for normal speech. The problem affects three generations of the family and has been studied since the 1990s. In 2001 geneticists determined that the affected members of the family all have a defective version of the FOXP2 gene.
In 2002 a team led by Wolfgang Enard at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany compared the human version of the FOXP2 gene with that of the chimpanzee, gorilla, orang-utan, rhesus macaque and mouse. They found that the gene is highly conserved, with differences of just three amino acid positions out of around 700 between the human version and the mouse version. But curiously two of these changes had occurred since the split between humans and chimps, a far more recent occurrence than the split between humans and mice. They suggested that these two changes might be critical to speech and language. The beneficial mutation has been positively selected for by natural selection and they estimated that it had become fixed in the human population at some stage in the last 200,000 years (Enard et al, 2002).
Klein believed the actual date would be 50,000 years, and that FOXP2 was the “smoking gun” responsible for the Great Leap Forward. But even a date of 200,000 years would rule out behavioural modernity in the Neanderthals, who had diverged from Homo sapiens much earlier.
Then in 2007 came a complete volte-face from the Max Planck Institute. The sequencing of the Neanderthal genome had revealed that Neanderthals possessed exactly the same version of FOXP2 as do modern humans (Krause et al, 2007). This not only pulled the rug from under Klein’s argument, it was also rather embarrassing for the group whose earlier 200,000 year estimate was now seen to be off by a factor of at least two. Dr. Svante Paabo, who was involved with both studies, admitted that the earlier estimates were “not flawed but rely on assumptions that are necessary but also universally known to be oversimplifications of the reality”.
Steven Mithen, Professor of Archaeology at Reading University, believes that the Neanderthals lacked what he refers to as “cognitive fluidity”.
In a theory first proposed in his 1996 book “The Prehistory of the Mind”, Mithen claims that the human brain originally had separate cognitive “domains” for different functions, such as social interaction, tool-making, food and resource gathering (“natural history”), etc. Modern human behaviour came about when the barriers between these domains broke down, allowing them to interact with each other. Art, religion and language all arose from the synergistic interactions between the various domains, but the Neanderthals quite literally never made the connection.
Mithen draws heavily on the work of Jerry Fodor, Annette Karmiloff-Smith, Michael Tomasello, Howard Gardiner, Leda Cosmides and John Tooby, but the idea of initially separate domains interacting may have been inspired in part by Julian Jaynes’ controversial theory about “bicameral minds”, proposed in 1976. However Mithen does not mention Jaynes’ theory (See Mithen, 1996; Fodor, 1983; Karmiloff-Smith, 1992; Tomasello, 1999; Gardiner, 1983 & 1999; Jaynes, 1976).
In 2005, in a book entitled “The Singing Neanderthal”, Mithen proposed the Neanderthals used a form of communication he refers to as Holistic, manipulative, multi-modal, musical and mimetic – abbreviated to Hmmmmm – which had features of both language and music. Instead of combining words to make up a range of meanings, Neanderthals and other archaic humans communicated with "holistic" utterances, which conveyed complete messages. While non-human primates use similar utterances to communicate information to others of their kind, the Neanderthals used them to manipulate the behaviour of others. While more complex than non-human primate communications, Hmmmm was very different to modern speech. Song, dance and mime made up the repertoire and while simpler forms of Hmmmmm were employed by earlier humans, it was taken onto a new level by the Neanderthals.
In the same work, Mithen argues strongly against behavioural modernity for the Neanderthals. This, he says, is evidenced by the “immense stability of their culture”, which endured with little change for over 200,000 years. Had they possessed language, it would have been impossible for their culture to have remained so stable and so “limited in scope”. Their lack of innovation was to be their undoing because “if there was ever a population of humans that needed to invent bows and arrows, the means for storing food, needles and thread, and so forth, it was the Neanderthals” for whom life was consequently so harsh that few lived beyond 35, leaving their populations only marginally viable (Mithen, 2005).
Richard Klein is even more damning of the Neanderthals: “It is not difficult to see why the Neanderthals failed to survive after behaviourally modern humans appeared. The archaeological record shows that in virtually every detectable aspect – artefacts, site modification, ability to adapt to extreme environments, subsistence, and so forth – the Neanderthals were behaviourally inferior to their modern successors, and to judge from their distinctive morphology, this behavioural inferiority may have been rooted in their biological makeup” (Klein, 1999).
But not everybody accepts the Great Leap Forward model or the behavioural inferiority of the Neanderthals. Such views are disputed among others by Stephen Oppenheimer, Robert Foley, Sally McBrearty and Alison S. Brooks, who claim there was no “big bang” and knowledge, skills and culture gradually developed over hundreds of millennia (see Oppenheimer, 2003; Lewin & Foley, 2004; McBrearty & Brooks, 2000). On this view, the technological differences between the Neanderthals and Cro-Magnons were cultural rather biological. The blade-based Mode IV tool technology of the latter, while superior to the Neanderthals’ Mousterian technology, did not require genetic mutation - anymore than writing genes, aeroplane genes and internet genes were required for these things to become possible.
Did Neanderthals and modern humans interbreed?
This is a topic of perennial interest, but conclusive evidence one way or the other is lacking. Although Neanderthals and modern humans both occupied sites in the Levant from 100,000 years ago, the two species were never present at the same time and the first contact between them may well not have occurred until modern humans first entered Europe, possibly 45,000 years ago according to a recent study (Anikovich et al, 2007).
There is little doubt in my mind that modern humans did on occasions have sex with Neanderthals. Even in the wild, closely-related species will on occasion mate, for example horses and donkeys, lions and tigers, and whales and dolphins. Such matings do lead to offspring and while these are generally infertile, they are usually viable. Given that modern humans will have sex with sheep, it seems inconceivable that they did not at some stage do so with Neanderthals. While Neanderthals would certainly have appeared strange to the incoming modern humans and vice-versa, they would not necessarily have seemed unattractive to each other. For a present-day human though, having sex with a Neanderthal might be a somewhat hazardous affair, given the considerably superior physical strength of the latter; but to the more robust Cro-Magnons this might have been less of an issue.
Could such unions have resulted in fertile offspring, or indeed any offspring? Given that we now know that there were probably no significant obstetric incompatibilities (see above) it does not seem unreasonable to suppose that hybridisation was possible, as with other closely-related species. But no convincing fossil evidence of Neanderthal/modern human hybridization has ever come to light, suggesting that it was rare if indeed it happened at all.
Claims that the 24,500 year old skeleton of a 4-year-old child found at Abrigo do Lagar Velho, Portugal in 1998 is an example of a hybrid (Duarte et al, 1999) are not widely accepted. Most researchers think that the Abrigo do Lagar Velho child simply was either an unusually stocky modern human child or one with a growth abnormality.
A 2006 study suggested that an adaptive allele (i.e. an advantageous version of a particular gene) of microcephalin (MCPH1), a gene linked with brain size, introgressed into modern humans from an extinct human lineage, quite possibly the Neanderthals (Evans et al, 2006). Haplogroup D as this version is known first appeared 37,000 years ago, closely corresponding to when modern humans began to colonise Europe. It is now the most common form throughout the world, except for in sub-Saharan Africa. The study suggested that its appearance might have resulted from cross-breeding between modern humans and Neanderthals. However this has now been ruled out following the publication of the first draft of the Neanderthal genome by a team led by Svante Paabo of the Max Planck Institute in Germany. The Neanderthal version of the microcephalin gene turns out to be the ancestral form found today in African populations.
Paabo has said that it seems overall Neanderthals have contributed, at most, a "very limited" fraction of the genetic variation found in contemporary human populations (quoted on BBC website, 12 Feb 2009).
Chris Stringer of the Natural History Museum in London believes that while interbreeding was most likely possible, it happened only rarely, with trivial impact on modern humans (quoted on BBC website, 12 Feb 2009).
The fate of the Neanderthals:
The most recent Neanderthal fossils are those from Gorham’s Cave, Gibraltar, suggesting that they occupied the cave until 28,000 years ago and possibly until as recently as 24,000 years ago (Finlayson et al, 2006). Modern humans may have first entered Europe 45,000 years ago, with Upper Palaeolithic sites on the Don River in Russia dating back to that time. Thereafter they spread rapidly across western and central Europe 42,000-40,000 years ago (Anikovich et al, 2007). Although there was certainly a long overlap before the Neanderthals finally disappeared, inevitably Homo sapiens has been widely blamed for their demise.
In his book Before the Dawn, published in 2007, Nicholas Wade refers to “the long struggle against the Neanderthals” and Stephen Oppenheimer suggests there was a “long and probably unfriendly stalemate” between the two species (Wade, 2007; Oppenheimer, 2003).
But the reality is that there is not a single piece of evidence for direct conflict between modern humans and the Neanderthals; nor indeed is there evidence of intercommunity violence between Cro-Magnon groups. While absence of evidence is not the same thing as evidence of absence, it does suggest that such events were not particularly common. Even if relations between the two species were consistently unfriendly, there is certainly no possibility that the Neanderthals were the victims of genocide. The kind of systematic slaughter that cost countless millions their lives during the last century was the work of state-level societies, not hunter-gatherer tribes.
On the other hand, if we reject an independent Neanderthal origin for the Châtelperronian industry (and it is hard to argue with Steven Mithen’s view about the improbable coincidence of this being so), then it implies at least a degree of cultural contact between Neanderthals and Cro-Magnons and that there must have been some co-operation between the two species.
When Europeans first began to exploit the New World, the infectious diseases they brought with them proved catastrophic to the indigenous people, who had no immunity to smallpox, typhus, cholera and measles. It has been suggested that the Neanderthals similarly fell victim to diseases to which the Cro-Magnons had long since become immune. But this seems improbable as pandemic-causing diseases require dense populations to be viable and did not arise in human populations until the emergence of urban societies. In addition many diseases have arisen in human populations by crossing the species gap from animals, something that would have been rare if not impossible in pre-agricultural times.
It seems more likely that regardless of whether or not the Neanderthals were behaviourally modern, the superior technology of the Cro-Magnons gave the latter the competitive edge in the constant quest for the next meal, for shelter and for other resources in Ice Age Europe. If this resulted in only a slight breeding advantage for the Cro-Magnons at the expense of the Neanderthals, then within a few thousand years the latter would have become extinct.
Climatic instability over the middle part of the last Ice Age may have exacerbated the Neanderthals problems, though as a recent study has shown, tying their final demise to specific climatic events is problematic, due to uncertainty in dating. The date of 28,000 years for the final Neanderthal occupation of Gorham’s Cave does not coincide with a period of unduly harsh conditions, but if the more recent date of 24,000 years ago is accepted, then this would correspond to a time of deteriorating conditions at the onset of the Last Glacial Maximum, which reached its maximum extent 20,000 years ago. Competition with the Cro-Magnons would have intensified as the latter migrated south from the higher latitudes (Tzedakis et al, 2007).
Regardless of the exact role played by the Cro-Magnons, the Neanderthals would have found themselves becoming increasingly marginalised, pushed to the peripheries of Europe. 10-20,000 years might seem like a long time, but this final chapter of the Neanderthal story accounts for no more than ten percent of their career; at the end of which they were gone forever.
References:
M. V. Anikovich, A. A. Sinitsyn, John F. Hoffecker, Vance T. Holliday, V. V. Popov, S. N. Lisitsyn, Steven L. Forman, G. M. Levkovskaya, G. A. Pospelova, I. E. Kuz’mina, N. D. Burova, Paul Goldberg, Richard I. Macphail, Biagio Giaccio, N. D. Praslov (2007): Early Upper Paleolithic in Eastern Europe and Implications for the Dispersal of Modern Humans, Science Vol. 315 p223 12 Jan 2007.
J. M. Bermudez de Castro, J. L. Arsuaga, E. Carbonell, A. Rosas, I. Martınez, M. Mosquera (1997): A Hominid from the Lower Pleistocene of Atapuerca, Spain: Possible Ancestor to Neandertals and Modern Humans, Science Vol. 276 30 May 1997.
Bogucki, P (1999): The Origins of Human Society, Blackwell Publishing.
Cameron D & Groves C (2004): Bones, Stones and Molecules: “Out of Africa” and Human Origins, Elsevier Academic Press.
Conroy G (1997): “Reconstructing Human Origins: A Modern Synthesis”, W.W. Norton & Co. Inc, New York, NY & London.
Dean MC, Stringer CB, Bromage TG (1986): Age at death of the Neanderthal child from Devil's Tower, Gibraltar and the implications for studies of general growth and development in Neanderthals, Am J Phys Anthropol. 1986 Jul; 70(3):301-9.
Diamond, J (1991) The Third Chimpanzee, Radius, London.
Cidalia Duarte, Joao Mauricio, Paul B. Pettitt, Pedro Souto, Erik Trinkaus,
Hans van Der Plicht & Joao Zilhao (1999): The Early Upper Paleolithic Human Skeleton from the Abrigo do Lagar Velho (Portugal) and Modern Human Emergence in Iberia, PNAS, USA 96 (1999): 7604-09.
Wolfgang Enard, Molly Przeworski, Simon E. Fisher, Cecilia S. L. Lai,
Victor Wiebe, Takashi Kitano, Anthony P. Monaco & Svante Paabo (2002): Molecular evolution of FOXP2, a gene involved in speech and language, Nature, Vol. 418 22 August 2002.
Patrick D. Evans, Nitzan Mekel-Bobrov, Eric J. Vallender, Richard R. Hudson, and Bruce T. Lahn (2006): Evidence that the adaptive allele of the brain size gene microcephalin introgressed into Homo sapiens from an archaic Homo lineage, PNAS November 28, 2006 vol. 103 no. 48.
Clive Finlayson, Francisco Giles Pacheco, Joaquın Rodrıguez-Vidal, Darren A. Fa, Jose Marıa Gutierrez Lopez, Antonio Santiago Perez, Geraldine Finlayson, Ethel Allue, Javier Baena Preysler, Isabel Caceres, Jose S. Carrion, Yolanda Fernandez Jalvo, Christopher P. Gleed-Owen, Francisco J. Jimenez Espejo, Pilar Lopez, Jose Antonio Lopez Saez, Jose Antonio Riquelme Cantal, Antonio Sanchez Marco, Francisco Giles Guzman, Kimberly Brown, Noemı Fuentes, Claire A. Valarino, Antonio Villalpando, Christopher B. Stringer, Francisca Martinez Ruiz & Tatsuhiko Sakamoto (2006): Late survival of Neanderthals at the southernmost extreme of Europe, Nature, Vol. 443 19 October 2006.
Fodor J (1983): “The Modularity of Mind”, MIT Press, Cambridge, MA.
Gardiner H (1983): “Frames of Mind”, Basic Books.
Gardiner H (1999): “Intelligence Reframed”, Basic Books.
Richard E. Green, Johannes Krause, Susan E. Ptak, Adrian W. Briggs, Michael T. Ronan, Jan F. Simons, Lei Du, Michael Egholm, Jonathan M. Rothberg, Maja Paunovic & Svante Paabo(2006): Analysis of one million base pairs of Neanderthal DNA, Nature 444, 330-336 (16 November 2006).
Helmuth, H. (1998): Body height, body mass and surface area of the Neanderthals, Zeitschrift für Morphologie und Anthropologie 82 (1): 1–12.
Jaynes J (1976): “The Origin of Consciousness in the Breakdown of the Bicameral Mind”, Mariner Books, USA.
Karmiloff-Smith A (1992): “Beyond Modularity”, MIT Press, Cambridge, MA.
Klein, R. (1999): The Human Career (2nd Edition), University of Chicago Press.
Klein R & Edgar B (2002): “The Dawn of Human Culture”, John Wiley & Sons Inc., New York.
Carles Lalueza-Fox, Holger Römpler, David Caramelli, Claudia Stäubert,
Giulio Catalano, David Hughes, Nadin Rohland, Elena Pilli, Laura Longo,
Silvana Condemi, Marco de la Rasilla, Javier Fortea, Antonio Rosas, Mark Stoneking, Torsten Schöneberg, Jaume Bertranpetit, Michael Hofreiter (2007): A Melanocortin 1 Receptor Allele Suggests Varying Pigmentation Among Neanderthals, Science, Vol. 318 30 November 2007.
Lewin, R and Foley, R (2004): Principles of Human Evolution (2nd edition), Blackwell Science Ltd.
McBrearty & Brooks (2000): The revolution that wasn’t: a new interpretation of the origin of modern human behaviour, Journal of Human Evolution (2000) 39, 453–563.
Mithen S (1996): “The Prehistory of the Mind”, Thames & Hudson.
Mithen S (2005): The Singing Neanderthal, Weidenfeld & Nicholson.
Oppenheimer S (2002): “Out of Eden”, Constable.
Rak Y, Arensburg B (1987): Kebara 2 Neanderthal pelvis: first look at a complete inlet, Am J Phys Anthropol. 1987 Jun;73(2):227-31.
Rak Y, Avishag Ginzburg and Eli Geffen (2002): Does Homo neanderthalensis play a role in modern human ancestry? The mandibular evidence, Am J Phys Anthropol. 119:199-204, 2002.
Rosenberg, Karen R (1985): Neandertal Birth Canals (Abstract), American Journal of Physical Anthropology 66:222.
Scarre C (2005) (Ed): “The human past”, Thames & Hudson.
Tomasello (1999): “The Cultural Origins of Human Cognition”, Harvard University Press, Cambridge, MA & London.
Trinkaus, E. (1984): Neandertal pubic morphology and gestation length. Current Anthropology. 25, 509-514.
Tzedakis PC, Hughen KA, Cacho I & Harvati K (2007): Placing the Neanderthals in a climatic context, Nature, Vol. 449 13 September 2007.
Wade N (2007): “Before the Dawn”, Duckworth.
Timothy D. Weaver, Charles C. Roseman & Chris B. Stringer (2008): Close correspondence between quantitative- and molecular-genetic divergence times for Neandertals and modern humans, PNAS March 25, 2008 vol. 105 no. 12 4647.
João Zilhão, Francesco d’Errico, Jean-Guillaume Bordes, Arnaud Lenoble, Jean-Pierre Texier and Jean-Philippe Rigaud (2006): Analysis of Aurignacian interstratification at the Châtelperronian -type site and implications for the behavioral modernity of Neandertals, PNAS August 15, 2006 vol. 103 no. 33.
© Christopher Seddon 2009
Saturday, 21 February 2009
Sunday, 8 February 2009
Gherkin
30 St Mary Axe, popularly known as the Gherkin, was designed by Norman Foster and opened in 2004. Seen against a foreground of more traditional buildings, it gives the impression of a vast spaceship that has touched down in the City of London.
© Christopher Seddon 2009
© Christopher Seddon 2009
Wednesday, 21 January 2009
Homo heidelbergensis
Introduction:
Homo heidelbergensis, or “archaic Homo sapiens”, is the name given to the large-brained hominins that appeared in Africa 600,000 years ago and migrated into Europe and possibly Asia. It is conventionally regarded as having given rise to modern humans in Africa and the Neanderthals in Europe.
The type specimen is the Mauer Mandible (Mauer 1), a virtually-complete lower jaw recovered from fluvial beds near the village of Mauer, in south-west Germany. The find was made on 21 October 1907 by a gravel-pit worker named Daniel Hartmann and described the following year by Professor Otto Schoetensack of the University of Heidelberg. The Mauer Mandible has been dated to 500,000 years old.
Until about ten years ago, the rather unsatisfactory term “archaic Homo sapiens” was used to describe any mid-Pleistocene hominin that wasn’t Homo erectus, Homo sapiens, or a Neanderthal. The latter was usually classified as a subspecies of Homo sapiens, i.e. H. s. neanderthalensis, but they are now generally regarded as a separate species. Consequently “archaic Homo sapiens” is itself regarded as a separate species, with the 1907 name Homo heidelbergensis having seniority under the rules of taxonomy.
As Manzi (2004) notes however this is no more than a revision of the old paradigm, with the substitution of a grade “archaic Homo sapiens” with a clade, Homo heidelbergensis, accompanied by the recognition of three distinct species, i.e. H. heidelbergensis, H. neanderthalensis and H. sapiens, with corresponding speciation events between the Middle and Late Pleistocene in Africa and Eurasia.
Whether or not Homo heidelbergensis is a genuine species or simply a grade of “Version 3.0 human" containing several species remains controversial.
Key Fossils:
Kabwe (Broken Hill), Zambia: Skull and several postcranial bones including a femur and a tibia (Broken Hill 1). It was found in an iron and zinc mine in Broken Hill, Northern Rhodesia (now Kabwe, Zambia) in 1921 by a Swiss miner named Tom Zwiglaar. Dating is uncertain, but probably between 700,000 and 400,000 years old. It has a cranial capacity of around 1100cc and was originally described as Homo rhodesiensis.
Lake Ndutu, Tanzania: a 400,000 year old cranium, found in 1973, with an estimated cranial capacity of 1100cc.
Bodo, Middle Awash, Ethiopia: a 670,000-600,000 year old cranium found in 1976 by a survey headed by Jon Kalb. Cranial capacity is 1300cc.
Sima de los Huesos, Atapuerca, Spain: 350,000 year old remains representing 28 individuals, including three nearly complete skulls, SH4 (cranial capacity 1390cc), SH5 (cranial capacity 1125cc) and SH6 (cranial capacity 1220cc).
Petralona, northern Greece: Skull discovered in cave system in 1960, dated 250,000 – 150,000 years old, with a cranial capacity of 1200cc.
La Caune de Arago, Tautavel in southern France: isolated teeth, cranial, mandibular and fragmentary postcranial remains belonging to at least four adults and three children, dated to approximately 450,000 years old. The distorted Arago 21 cranium has an estimated capacity of 1150cc.
Mauer, Germany: the Mauer Mandible, as mentioned above.
Steinheim, Germany: a distorted but nearly complete cranium found in a gravel pit 1933 by Karl Sigrist. It is believed to be 350,000-250,000 years old. The cranial capacity is 1100cc.
Boxgrove, England: a partial tibia discovered in 1994 dated to 423,000-362,000 years old, associated with Acheulian tools.
Swanscombe, England: three skull fragments belonging to the same individual recovered between 1935 and 1955; believed to be 300,000-200,000 years old and popularly known as Swanscombe Man, though now thought to be female. The cranial capacity has been estimated at 1325cc.
Dali, Shaanxi Province, China: a 250,000 year old cranium discovered by Shuntang Liu in 1978, with a cranial capacity of 1120cc.
Jinniu Shan: cranium, vertebrae, ribs, pelvis, patella and limb bones discovered in 1984. The cranial capacity is 1300cc and the remains are believed to be 250,000 years old.
Description:
Manzi (2004) selects the Middle Pliocene fossils from Kabwe, Petralona and Dali fossils as being typical of Homo heidelbergensis. They have a “transitional aspect” between earlier and more recent hominins which include both primitive and derived traits. Primitive or “archaic” features include a heavily-built cranial structure with massive brow ridges; crests in the temporo-occipital region, including erectus-like occipital and angular tori; a low and antero-posteriorly elongated cranial vault; a protruding and large facial skeleton; and the absence of a modern chin. These traits are however reduced in comparison to Homo ergaster/erectus.
The main derived feature is that the general shape of the cranial vault is consistent with increased brain-size. The frontal is less receding than it is in earlier hominins; the parietal profile is more convex along the mid-sagittal plane and less angled in coronal sections; and the occipital squama is more vertical and arched.
The cranial capacity is typically between 1100-1300cc, around 90% of that of modern humans, a considerable increase on that of Homo erectus/ergaster.
Affinities to other hominins:
The view that this species evolved in Africa about 600,000 years ago, then migrated into Europe, and that the two lineages led to respectively Homo sapiens and the Neanderthals, is probably as convincing as any of the alternatives.
Homo antecessor (known only from Spain) has recently been touted as ancestral to Homo heidelbergensis, suggesting that either the latter was a European species that later migrated back into Africa, or that Homo antecessor evolved in Africa.
Another possibility is that African and European Homo heidelbergensis are different species, with the Bodo Cranium an early example of the former. On this view, the African species would take the name originally assigned to the Bodo Cranium, Homo rhodesiensis. However the sudden increase in brain size to 90% of the modern average seen in the fossil record at around 600,000 years ago, after remaining more or less static at 65% during the previous 1.2 million years, does suggest a punctuated event which in turn suggests a single species.
Just about all that can be safely said at the present time is that our understanding is very incomplete!
Technology:
Homo heidelbergensis is associated with the same Acheulian (Mode II) technology as that originated by Homo ergaster 1.65 million years ago; however later Acheulian hand-axes are thinner, more symmetric and more extensively trimmed. Some authorities describe this technology as “Late Acheulian”. It is possible that its appearance is connected with the emergence of Homo heidelbergensis and is a product of this species greater cognitive abilities.
References:
J. M. Bermudez de Castro, J. L. Arsuaga, E. Carbonell, A. Rosas, I. Martınez, M. Mosquera (1997): A Hominid from the Lower Pleistocene of Atapuerca, Spain: Possible Ancestor to Neandertals and Modern Humans, Science Vol. 276 30 May 1997.
Cameron D & Groves C (2004): Bones, Stones and Molecules: “Out of Africa” and Human Origins, Elsevier Academic Press.
Conroy G (1997): “Reconstructing Human Origins: A Modern Synthesis”, W.W. Norton & Co. Inc, New York, NY & London.
Klein, R. (1999): The Human Career (2nd Edition), University of Chicago Press.
Klein R & Edgar B (2002): “The Dawn of Human Culture”, John Wiley & Sons Inc., New York.
Lewin, R and Foley, R 2004: Principles of Human Evolution (2nd edition), Blackwell Science Ltd.
Manzi G (2004): Human Evolution at the Matuyama-Brunhes
Boundary, Evolutionary Anthropology 13:11–24 (2004).
Scarre C (2005) (Ed): “The human past”, Thames & Hudson.
Stringer C & Andrews P (2005): “The Complete World of Human Evolution”, Thames & Hudson.
© Christopher Seddon 2009
Homo heidelbergensis, or “archaic Homo sapiens”, is the name given to the large-brained hominins that appeared in Africa 600,000 years ago and migrated into Europe and possibly Asia. It is conventionally regarded as having given rise to modern humans in Africa and the Neanderthals in Europe.
The type specimen is the Mauer Mandible (Mauer 1), a virtually-complete lower jaw recovered from fluvial beds near the village of Mauer, in south-west Germany. The find was made on 21 October 1907 by a gravel-pit worker named Daniel Hartmann and described the following year by Professor Otto Schoetensack of the University of Heidelberg. The Mauer Mandible has been dated to 500,000 years old.
Until about ten years ago, the rather unsatisfactory term “archaic Homo sapiens” was used to describe any mid-Pleistocene hominin that wasn’t Homo erectus, Homo sapiens, or a Neanderthal. The latter was usually classified as a subspecies of Homo sapiens, i.e. H. s. neanderthalensis, but they are now generally regarded as a separate species. Consequently “archaic Homo sapiens” is itself regarded as a separate species, with the 1907 name Homo heidelbergensis having seniority under the rules of taxonomy.
As Manzi (2004) notes however this is no more than a revision of the old paradigm, with the substitution of a grade “archaic Homo sapiens” with a clade, Homo heidelbergensis, accompanied by the recognition of three distinct species, i.e. H. heidelbergensis, H. neanderthalensis and H. sapiens, with corresponding speciation events between the Middle and Late Pleistocene in Africa and Eurasia.
Whether or not Homo heidelbergensis is a genuine species or simply a grade of “Version 3.0 human" containing several species remains controversial.
Key Fossils:
Kabwe (Broken Hill), Zambia: Skull and several postcranial bones including a femur and a tibia (Broken Hill 1). It was found in an iron and zinc mine in Broken Hill, Northern Rhodesia (now Kabwe, Zambia) in 1921 by a Swiss miner named Tom Zwiglaar. Dating is uncertain, but probably between 700,000 and 400,000 years old. It has a cranial capacity of around 1100cc and was originally described as Homo rhodesiensis.
Lake Ndutu, Tanzania: a 400,000 year old cranium, found in 1973, with an estimated cranial capacity of 1100cc.
Bodo, Middle Awash, Ethiopia: a 670,000-600,000 year old cranium found in 1976 by a survey headed by Jon Kalb. Cranial capacity is 1300cc.
Sima de los Huesos, Atapuerca, Spain: 350,000 year old remains representing 28 individuals, including three nearly complete skulls, SH4 (cranial capacity 1390cc), SH5 (cranial capacity 1125cc) and SH6 (cranial capacity 1220cc).
Petralona, northern Greece: Skull discovered in cave system in 1960, dated 250,000 – 150,000 years old, with a cranial capacity of 1200cc.
La Caune de Arago, Tautavel in southern France: isolated teeth, cranial, mandibular and fragmentary postcranial remains belonging to at least four adults and three children, dated to approximately 450,000 years old. The distorted Arago 21 cranium has an estimated capacity of 1150cc.
Mauer, Germany: the Mauer Mandible, as mentioned above.
Steinheim, Germany: a distorted but nearly complete cranium found in a gravel pit 1933 by Karl Sigrist. It is believed to be 350,000-250,000 years old. The cranial capacity is 1100cc.
Boxgrove, England: a partial tibia discovered in 1994 dated to 423,000-362,000 years old, associated with Acheulian tools.
Swanscombe, England: three skull fragments belonging to the same individual recovered between 1935 and 1955; believed to be 300,000-200,000 years old and popularly known as Swanscombe Man, though now thought to be female. The cranial capacity has been estimated at 1325cc.
Dali, Shaanxi Province, China: a 250,000 year old cranium discovered by Shuntang Liu in 1978, with a cranial capacity of 1120cc.
Jinniu Shan: cranium, vertebrae, ribs, pelvis, patella and limb bones discovered in 1984. The cranial capacity is 1300cc and the remains are believed to be 250,000 years old.
Description:
Manzi (2004) selects the Middle Pliocene fossils from Kabwe, Petralona and Dali fossils as being typical of Homo heidelbergensis. They have a “transitional aspect” between earlier and more recent hominins which include both primitive and derived traits. Primitive or “archaic” features include a heavily-built cranial structure with massive brow ridges; crests in the temporo-occipital region, including erectus-like occipital and angular tori; a low and antero-posteriorly elongated cranial vault; a protruding and large facial skeleton; and the absence of a modern chin. These traits are however reduced in comparison to Homo ergaster/erectus.
The main derived feature is that the general shape of the cranial vault is consistent with increased brain-size. The frontal is less receding than it is in earlier hominins; the parietal profile is more convex along the mid-sagittal plane and less angled in coronal sections; and the occipital squama is more vertical and arched.
The cranial capacity is typically between 1100-1300cc, around 90% of that of modern humans, a considerable increase on that of Homo erectus/ergaster.
Affinities to other hominins:
The view that this species evolved in Africa about 600,000 years ago, then migrated into Europe, and that the two lineages led to respectively Homo sapiens and the Neanderthals, is probably as convincing as any of the alternatives.
Homo antecessor (known only from Spain) has recently been touted as ancestral to Homo heidelbergensis, suggesting that either the latter was a European species that later migrated back into Africa, or that Homo antecessor evolved in Africa.
Another possibility is that African and European Homo heidelbergensis are different species, with the Bodo Cranium an early example of the former. On this view, the African species would take the name originally assigned to the Bodo Cranium, Homo rhodesiensis. However the sudden increase in brain size to 90% of the modern average seen in the fossil record at around 600,000 years ago, after remaining more or less static at 65% during the previous 1.2 million years, does suggest a punctuated event which in turn suggests a single species.
Just about all that can be safely said at the present time is that our understanding is very incomplete!
Technology:
Homo heidelbergensis is associated with the same Acheulian (Mode II) technology as that originated by Homo ergaster 1.65 million years ago; however later Acheulian hand-axes are thinner, more symmetric and more extensively trimmed. Some authorities describe this technology as “Late Acheulian”. It is possible that its appearance is connected with the emergence of Homo heidelbergensis and is a product of this species greater cognitive abilities.
References:
J. M. Bermudez de Castro, J. L. Arsuaga, E. Carbonell, A. Rosas, I. Martınez, M. Mosquera (1997): A Hominid from the Lower Pleistocene of Atapuerca, Spain: Possible Ancestor to Neandertals and Modern Humans, Science Vol. 276 30 May 1997.
Cameron D & Groves C (2004): Bones, Stones and Molecules: “Out of Africa” and Human Origins, Elsevier Academic Press.
Conroy G (1997): “Reconstructing Human Origins: A Modern Synthesis”, W.W. Norton & Co. Inc, New York, NY & London.
Klein, R. (1999): The Human Career (2nd Edition), University of Chicago Press.
Klein R & Edgar B (2002): “The Dawn of Human Culture”, John Wiley & Sons Inc., New York.
Lewin, R and Foley, R 2004: Principles of Human Evolution (2nd edition), Blackwell Science Ltd.
Manzi G (2004): Human Evolution at the Matuyama-Brunhes
Boundary, Evolutionary Anthropology 13:11–24 (2004).
Scarre C (2005) (Ed): “The human past”, Thames & Hudson.
Stringer C & Andrews P (2005): “The Complete World of Human Evolution”, Thames & Hudson.
© Christopher Seddon 2009
Saturday, 17 January 2009
Homo ergaster
Introduction:
Homo ergaster ("working man") is an extinct human species that is known in the fossil record in Africa from possibly > 1.9 million years ago (KNM-ER 2598) and more securely 1.7-18 million years ago (KNM-ER 3733). By 600,000 years ago, it had been supplanted by the more advanced Homo heidelbergensis (“archaic Homo sapiens”).
Homo ergaster is usually assumed to have evolved from Homo habilis and to be the first human species to have left Africa. It is widely recognised as the stem species for later humans, including ourselves. It is now thought to be distinct from Homo erectus, which persisted in Asia until as recently as 50,000 to 30,000 years ago.
Homo ergaster was described in 1975 by Colin Groves and Vratislav Mazak. The type specimen is KNM-ER 992, a mandible discovered in 1971 at Koobi Fora, East Turkana, in Kenya.
Fossil record:
Homo ergaster is known from fossils recovered in East and West Turkana, Kenya; Swartkrans, South Africa; Olduvai Gorge, Tanzania; Bouri, Ethiopia; Buia, Eritrea and possibly from Dmanisi, Georgia. Key fossils include from these locations include:
From Koobi Fora, East Turkana: KNM-ER 3733, a cranium discovered in 1975 by Bernard Ngeneo, believed to be 1.8-1.7 million years old.
KNM-ER 3883, a cranium discovered in 1976 by Richard Leakey, 1.4-1.6 million years old.
KNM-ER 1808, cranial and post-cranial remains, discovered in 1973 by Kamoya Kimeu, believed to be 1.5 million years old. These remains are thought to be from a female and show coarse bone growths suggesting hypervitaminosis A, a lethal condition arising from excessive Vitamin A consumption. This could have arisen from consumption of carnivore liver or possibly bee brood. That KNM-ER 1808 survived long enough for the pathology to show up in her bones implies that she was cared for by others of her own kind.
KNM-ER 2958, a partial occipital bone is possibly > 1.9m years old. If so, it is the earliest fossil evidence for Homo ergaster.
From West Turkana: The “Turkana Boy” (KNM-WT 15000), an almost-complete adolescent male skull and skeleton discovered in August 1984 by Kamoya Kimeu on the banks of the Nariokotome River, dated to 1.33-1.64 millon years old. One of the most important fossil finds ever made, the Turkana Boy is even more complete than “Lucy”. Based on dental irruption, he was 11-12 years old at death.
From Swartkrans: SK 847, a partial cranium noted in 1969 at the Transvaal Museum, Pretoria by Ronald Clarke, though discovered twenty years earlier by museum palaeontologists Robert Broom and John Robinson, 1.0-1.5 million years old.
The “Daka Cranium” (BOU-VP 2/66), from Bouri, Middle Awash, Ethiopia, a 1.0 million year old calvaria with a cranial capacity of 995cc, discovered 1997 by W. H. Gilbert, may belong to Homo ergaster but both it and a similar cranium from Buia, Eritrea may represent a migration from Asia back into Africa by Homo erectus.
OH9 and OH 12 from Olduvai Gorge, Tanzania. OH9, discovered by Louis Leakey in 1960 is a 1.2 million year old cranium provisionally designated Homo leakeyi. It has a cranial capacity of 1067cc. OH 12, discovered by Margaret Cropper in 1962 is an 830,000-620,000 year old fragmentary cranium.
D2700 from Dmanisi, Georgia, is a skull dated at 1.95-1.77 million years old. The brain-case is very small, just 600cc, more consistent with Homo habilis, but postcranial remains from the same site suggest Homo ergaster affinities. These hominins have been described as a separate species, Homo georgicus.
Description:
Much of our knowledge of Homo ergaster comes from study of the Turkana Boy, who stood 1.62m (5ft3) at death and would have attained at least 1.82m (6ft) had he reached adulthood.
But his brain, which was almost fully-grown, had a volume of just 880cc, only 2/3rds that of a modern human. Mature Homo ergaster had a cranial capacity of around 900cc (Klein, 1999) though it ranged from as little as 600cc (D2700) to as much as 1100cc (OH 9). Although the average is rather more than that of Homo habilis, the effective difference is only small given H. ergaster’s greater stature.
H. ergaster possessed the characteristic long, low brain-case of pre-sapiens human species; a flat and receding forehead; a bony brow-ridge over the eyes. The nose projected forward, with downward-orientated nostrils, similar to a modern human, again unlike the more ape-like H. habilis. But the jaws were massive and prognathic (jutting) and the teeth were intermediate in size between H. habilis and modern humans. They were completely chinless.
The rib-cage is barrel-shaped rather than conical, the pelvis is narrower and in body proportions, very much like modern humans, with lower limbs indicating a full striding gait. Homo ergaster was a fully-committed terrestrial biped, unlike Homo habilis, which retained relatively longer arms, shorter legs and a conical ribcage: remnants of an arboreal past now finally abandoned.
The narrower pelvis increases the energy efficiency of muscles involved in bipedal movement, but this forced the lower part of the ribcage to narrow. To retain the same lung capacity, the upper part of the ribcage expanded to give it its modern barrel shape. The down side is that the female birth canal narrowed. This in turn would have restricted antenatal brain growth. The very long postnatal dependency of modern humans might have had its origins with Homo ergaster.
These changes would have also forced a reduction in the size of the digestive tract, which could only have happened in conjunction with higher quality food. This suggests consumption of more meat, tubers, bulbs, etc and the possible use of fire for cooking, but there is no hard evidence for either.
Homo ergaster colonised dryer, more seasonal African environments, where there was relatively little surface water or shade. Its physique is not unlike that of present-day humans living in equatorial East Africa, who have slim bodies and long limbs; a body-shape that gives a higher surface area to volume ratio than the stockier build of, say, an Eskimo and is more efficient at dissipating (as opposed to conserving) heat.
Under hot conditions, the projecting, human-like nose would act as a condenser, preventing moisture from being exhaled and so wasted. It is likely that Homo ergaster was almost naked, like a modern human, but unlike any previously-existing hominin. This would have greatly aided heat dissipation. Like modern Africans, Homo ergaster was almost certainly dark-skinned, to protect against skin cancer. (Scarre, 2005; Cameron & Groves, 2004).
Because the natal brain size was less than that of modern humans, the birth canal, though still problematic, was smaller than that of modern humans. Consequently Homo ergaster may have been a more efficient biped than ourselves, and was probably a superb all-round runner that would have left our best athletes trailing in its wake. Enhanced middle and long-distance running abilities would have given them an edge when hunting; conversely when the tables were turned, sprinting abilities would have helped them to escape predators.
Origins:
As noted above, the widely-accepted view is that Homo ergaster evolved from Homo habilis. Although Homo rudolfensis is also a possible ancestor, it seems likely that this taxon is off the line of human evolution and should be removed from Homo altogether (Cameron & Groves, 2004).
Another possibility is that both Homo habilis and H. ergaster both evolved from a common ancestor around 2.3 million years ago. Spoor et al (2007) note that both species were sympatric in the Turkana Basin for approximately 400,000 years. They believe that this is a more likely explanation than the alternative, which is a Homo ergaster split from an earlier population of Homo habilis, with the Turkana Basin being a region of secondary contact between the two species. Cameron and Groves (2004) take the opposite view, pointing out that Homo ergaster does not appear in the fossil record until much later than Homo habilis.
If the second scenario is correct, and Homo ergaster split in a sudden “punctuated” evolutionary event, a possible cause would be the increase in seasonal rainfall and aridity that occurred across Africa with the onset of the Pleistocene, 1.8 million years ago.
On the other hand it is possible that from 3 to 2 million years ago in Africa there existed a “bush” or complex of closely-related but distinct hominin species, and that Homo habilis and H. ergaster could have emerged from totally separate branches. If this is correct, then there are still many species of hominin remaining undiscovered.
Relationship to Homo erectus:
It used to be the general view that the “Version 2.0 humans” living in Africa and Europe until 600,000 years ago and Asia until possibly 50,000-30,000 years ago belonged to a single species, Homo erectus. But this view has fallen out of fashion. On average, the African skulls tend to be higher-domed and thinner-walled than those from East Asia, and they have less massive faces and brow-ridges. Accordingly the African hominins are usually now classified as Homo ergaster, with the designation H. erectus reserved for Asian fossils. Many sources do still lump both together as Homo erectus or use the term “African Homo erectus” in preference to H. ergaster.
The view that Homo ergaster left Africa and evolved into Homo erectus, while Africa remained exclusively populated by stay-at-home H. ergaster, is almost certainly an oversimplification.
The presence of the 1.95-1.77 million years old ergaster-like skulls at Dmanisi show that humans had left Africa by then, but whether or not these hominins can be included in Homo ergaster or were ancestral the Homo erectus in Asia remains a matter for debate.
The discovery of an erectus-like hominin at Ceprano, Italy, in 1994 and its similarity to the Olduvai hominin OH 9 (Clarke, 2000) has led to the view that there was a migration back into Africa by Homo erectus. In addition to OH 9, the more recent OH 12, the “Daka Cranium” (BOU-VP 2/66), from Bouri and the similar cranium from Buia have been proposed as examples of “Into Africa” Homo erectus rather than Homo ergaster (Cameron & Groves, 2004). The partial skullcap OH 9 has massive brow-ridges, thick walls and angular rear profile typical of East Asian Homo erectus, but in other characteristics it is like Homo ergaster. The Buia and Daka skulls show only minor differences from earlier Homo ergaster (Scarre, 2005).
Berhane Asfaw argues that “the Daka cranium confirms previous suggestions that geographic subdivision of early H. erectus into separate species lineages is biologically misleading, artificially inflating early Pleistocene species diversity. Rather, the Daka calvaria is consistent with the hypothesis of a widespread, moderately polymorphic and polytypic species [i.e. Homo erectus] at 1.0Myr” Asfaw et al (2002).
Subsequent evolutionary career:
The traditional view is that around 600,000 years ago, Homo ergaster (or African Homo erectus) evolved into the larger-brained “archaic Homo sapiens” from which two distinct subspecies, the Neanderthals and modern Homo sapiens (us), eventually arose. The currently popular view represents only a slight updating of this paradigm in that “archaic Homo sapiens” is now seen as a distinct species, Homo heidelbergensis. This species migrated into Europe, where it evolved into Homo neanderthalensis (the Neanderthals). Meanwhile, H. heidelbergensis in Africa evolved into Homo sapiens about 200,000 years ago. While it does seem likely that African Homo erectus (whatever this may be) did evolve into larger-brained hominins it is problematic as to whether there was just one successor species or several; from which of these Homo sapiens eventually arose; of if indeed the progenitor species for Homo sapiens was African or a European species that migrated back into Africa.
Technology:
The earliest Homo ergaster remains, including the Dmanisi hominins, are associated with the Oldowan (Mode I) tool tradition. At about 1.65 million years ago these primitive tools give way to the teardrop shaped “hand-axes” of the Acheulian (Mode II) tradition, named for Saint-Acheul in Northern France, where the first examples were found at in the mid-19th Century. The oldest known Acheulian tools are dated to 1.65 million years ago from West Turkana, Kenya and 1.5-1.4 million years ago from Konso, Ethiopia, East Turkana, Kenya and Peninj, near Olduvai Gorge, Tanzania (Scarre, 2005).
The Acheulian hand-axe tradition endured with little change until it was finally abandoned 250,000 years ago. It has been described as displaying a “variable sameness” that strikes “even enthusiasts as monotonous”. The tradition does however represent a considerable advance on its predecessor as it is necessary for the maker to preconceive the form of the finished tool from a block of raw material. The 3D symmetry often shown by the axes indicate their makers were intent on imposing form on the artefact rather than just creating a sharp edge as in the Oldowan tradition. This is very difficult and requires forward planning (Mithen, 1996).
Despite the name, the function of these often beautifully-crafted hand-axes remains conjectural. At some sites such as Melka Kunture in Ethiopia, Olorgesailie in Kenya, Isimila in Tanzania and Kalambo Falls, hand-axes occur in large numbers and appear to have been discarded soon after manufacture, with no sign of wear, suggesting that they were never used. Another major puzzle is that they are often too large to be useful (see, for example, the fine example in the Natural History Museum in Kensington).
One theory (Kohn & Mithen, 1999) proposes that the axes were made to impress prospective mates. When a female saw a large, symmetrical axe, she might conclude that its maker possessed the right attributes to father successful offspring. The axe, having served its purpose (or not) would then be discarded. This – like the elaborate bower of the male bower bird – would be an example of the extended phenotype of a species playing a role in sexual selection (Dawkins, 1982).
Regardless of whether or not the mate selection hypothesis is true, the hand-axes almost certainly were used as tools. Experiments have shown them to be effective for butchery purposes; some may have been used as a discus for bringing down prey; others could have been used for chopping and scraping wood. Klein and Edgar (2002) liken the Acheulian hand-axe to a Swiss army knife.
Another issue with the hand-axes is that while they are ubiquitous in Africa and western Eurasia, they are not found east of Northern India. This was first noted by American archaeologist Hallam Movius in 1948. The “Movius Line” has stood the test of time and two theories have been proposed to explain it. One is that the ancestors of those living east of the Movius Line left Africa before the hand-axes were invented. The other possibility is that the migrants from Africa passed through a region lacking suitable materials to make the axes, and by the time they emerged from it, the tradition had been forgotten.
Recent discoveries support the first possibility. Hominin remains such as the Mojokarta Child [Homo erectus] from Java have now been dated to 1.81 million years ago and the Dmanisi hominins are at least 1.77 million years old, predating the earliest-known Acheulian hand-axes.
References:
Berhane Asfaw, W. Henry Gilbert, Yonas Beyene, William K. Hart,
Paul R. Rennek, Giday WoldeGabriel, Elisabeth S. Vrba & Tim D. White (2002): Remains of Homo erectus from Bouri, Middle Awash, Ethiopia, Nature Vol. 416, 21 March 2002.
A. Ascenzi, F. Mallegni, G. Manzi, A. G. Segre & E. Segre Naldini (2000): A re-appraisal of Ceprano calvaria affinities with Homo erectus, after the new reconstruction, Journal of Human Evolution (2000) 39, 443–450.
Cameron D & Groves C (2004): Bones, Stones and Molecules: “Out of Africa” and Human Origins, Elsevier Academic Press.
Clarke R.J (2000): A corrected reconstruction and interpretation of the Homo erectus calvaria from Ceprano, Italy, Journal of Human Evolution, Volume 39, Number 4, October 2000, pp. 433-442.
Conroy G (1997): “Reconstructing Human Origins: A Modern Synthesis”, W.W. Norton & Co. Inc, New York, NY & London.
Dawkins R (1982): “The Extended Phenotype”, Oxford University Press.
Klein, R. (1999): The Human Career (2nd Edition), University of Chicago Press.
Klein R & Edgar B (2002): “The Dawn of Human Culture”, John Wiley & Sons Inc., New York.
Kohn M & Mithen S (1999): “Handaxes: products of sexual selection?” Antiquity 73: 518-526.
Lewin, R and Foley, R 2004: Principles of Human Evolution (2nd edition), Blackwell Science Ltd.
Manzi G (2004): Human Evolution at the Matuyama-Brunhes
Boundary, Evolutionary Anthropology 13:11–24 (2004)
G. Manzi, F. Mallegni, and A. Ascenzi (2001): A cranium for the earliest Europeans: Phylogenetic position of the hominid from Ceprano, Italy, PNAS August 14, 2001 vol. 98 no. 17 10013.
Mithen S (1996): “The Prehistory of the Mind”, Thames & Hudson.
Scarre C (2005) (Ed): “The human past”, Thames & Hudson.
F. Spoor, M. G. Leakey, P. N. Gathogo, F. H. Brown, S. C. Anton, I. McDougall, C. Kiarie, F. K. Manthi & L. N. Leakey (2007): Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya, Nature Vol 448 9 August 2007.
Gen Suwa, Berhane Asfaw, Yohannes Haile-Selassie, Tim White, Shigehiro Katoh, Giday WoldeGabriel, William K. Hart, Hideo Nakaya, Yonas Beyene (2007): Early Pleistocene Homo erectus fossils from Konso, southern Ethiopia, Anthropological Science, Vol. 115, 133–151, 2007.
© Christopher Seddon 2009
Homo ergaster ("working man") is an extinct human species that is known in the fossil record in Africa from possibly > 1.9 million years ago (KNM-ER 2598) and more securely 1.7-18 million years ago (KNM-ER 3733). By 600,000 years ago, it had been supplanted by the more advanced Homo heidelbergensis (“archaic Homo sapiens”).
Homo ergaster is usually assumed to have evolved from Homo habilis and to be the first human species to have left Africa. It is widely recognised as the stem species for later humans, including ourselves. It is now thought to be distinct from Homo erectus, which persisted in Asia until as recently as 50,000 to 30,000 years ago.
Homo ergaster was described in 1975 by Colin Groves and Vratislav Mazak. The type specimen is KNM-ER 992, a mandible discovered in 1971 at Koobi Fora, East Turkana, in Kenya.
Fossil record:
Homo ergaster is known from fossils recovered in East and West Turkana, Kenya; Swartkrans, South Africa; Olduvai Gorge, Tanzania; Bouri, Ethiopia; Buia, Eritrea and possibly from Dmanisi, Georgia. Key fossils include from these locations include:
From Koobi Fora, East Turkana: KNM-ER 3733, a cranium discovered in 1975 by Bernard Ngeneo, believed to be 1.8-1.7 million years old.
KNM-ER 3883, a cranium discovered in 1976 by Richard Leakey, 1.4-1.6 million years old.
KNM-ER 1808, cranial and post-cranial remains, discovered in 1973 by Kamoya Kimeu, believed to be 1.5 million years old. These remains are thought to be from a female and show coarse bone growths suggesting hypervitaminosis A, a lethal condition arising from excessive Vitamin A consumption. This could have arisen from consumption of carnivore liver or possibly bee brood. That KNM-ER 1808 survived long enough for the pathology to show up in her bones implies that she was cared for by others of her own kind.
KNM-ER 2958, a partial occipital bone is possibly > 1.9m years old. If so, it is the earliest fossil evidence for Homo ergaster.
From West Turkana: The “Turkana Boy” (KNM-WT 15000), an almost-complete adolescent male skull and skeleton discovered in August 1984 by Kamoya Kimeu on the banks of the Nariokotome River, dated to 1.33-1.64 millon years old. One of the most important fossil finds ever made, the Turkana Boy is even more complete than “Lucy”. Based on dental irruption, he was 11-12 years old at death.
From Swartkrans: SK 847, a partial cranium noted in 1969 at the Transvaal Museum, Pretoria by Ronald Clarke, though discovered twenty years earlier by museum palaeontologists Robert Broom and John Robinson, 1.0-1.5 million years old.
The “Daka Cranium” (BOU-VP 2/66), from Bouri, Middle Awash, Ethiopia, a 1.0 million year old calvaria with a cranial capacity of 995cc, discovered 1997 by W. H. Gilbert, may belong to Homo ergaster but both it and a similar cranium from Buia, Eritrea may represent a migration from Asia back into Africa by Homo erectus.
OH9 and OH 12 from Olduvai Gorge, Tanzania. OH9, discovered by Louis Leakey in 1960 is a 1.2 million year old cranium provisionally designated Homo leakeyi. It has a cranial capacity of 1067cc. OH 12, discovered by Margaret Cropper in 1962 is an 830,000-620,000 year old fragmentary cranium.
D2700 from Dmanisi, Georgia, is a skull dated at 1.95-1.77 million years old. The brain-case is very small, just 600cc, more consistent with Homo habilis, but postcranial remains from the same site suggest Homo ergaster affinities. These hominins have been described as a separate species, Homo georgicus.
Description:
Much of our knowledge of Homo ergaster comes from study of the Turkana Boy, who stood 1.62m (5ft3) at death and would have attained at least 1.82m (6ft) had he reached adulthood.
But his brain, which was almost fully-grown, had a volume of just 880cc, only 2/3rds that of a modern human. Mature Homo ergaster had a cranial capacity of around 900cc (Klein, 1999) though it ranged from as little as 600cc (D2700) to as much as 1100cc (OH 9). Although the average is rather more than that of Homo habilis, the effective difference is only small given H. ergaster’s greater stature.
H. ergaster possessed the characteristic long, low brain-case of pre-sapiens human species; a flat and receding forehead; a bony brow-ridge over the eyes. The nose projected forward, with downward-orientated nostrils, similar to a modern human, again unlike the more ape-like H. habilis. But the jaws were massive and prognathic (jutting) and the teeth were intermediate in size between H. habilis and modern humans. They were completely chinless.
The rib-cage is barrel-shaped rather than conical, the pelvis is narrower and in body proportions, very much like modern humans, with lower limbs indicating a full striding gait. Homo ergaster was a fully-committed terrestrial biped, unlike Homo habilis, which retained relatively longer arms, shorter legs and a conical ribcage: remnants of an arboreal past now finally abandoned.
The narrower pelvis increases the energy efficiency of muscles involved in bipedal movement, but this forced the lower part of the ribcage to narrow. To retain the same lung capacity, the upper part of the ribcage expanded to give it its modern barrel shape. The down side is that the female birth canal narrowed. This in turn would have restricted antenatal brain growth. The very long postnatal dependency of modern humans might have had its origins with Homo ergaster.
These changes would have also forced a reduction in the size of the digestive tract, which could only have happened in conjunction with higher quality food. This suggests consumption of more meat, tubers, bulbs, etc and the possible use of fire for cooking, but there is no hard evidence for either.
Homo ergaster colonised dryer, more seasonal African environments, where there was relatively little surface water or shade. Its physique is not unlike that of present-day humans living in equatorial East Africa, who have slim bodies and long limbs; a body-shape that gives a higher surface area to volume ratio than the stockier build of, say, an Eskimo and is more efficient at dissipating (as opposed to conserving) heat.
Under hot conditions, the projecting, human-like nose would act as a condenser, preventing moisture from being exhaled and so wasted. It is likely that Homo ergaster was almost naked, like a modern human, but unlike any previously-existing hominin. This would have greatly aided heat dissipation. Like modern Africans, Homo ergaster was almost certainly dark-skinned, to protect against skin cancer. (Scarre, 2005; Cameron & Groves, 2004).
Because the natal brain size was less than that of modern humans, the birth canal, though still problematic, was smaller than that of modern humans. Consequently Homo ergaster may have been a more efficient biped than ourselves, and was probably a superb all-round runner that would have left our best athletes trailing in its wake. Enhanced middle and long-distance running abilities would have given them an edge when hunting; conversely when the tables were turned, sprinting abilities would have helped them to escape predators.
Origins:
As noted above, the widely-accepted view is that Homo ergaster evolved from Homo habilis. Although Homo rudolfensis is also a possible ancestor, it seems likely that this taxon is off the line of human evolution and should be removed from Homo altogether (Cameron & Groves, 2004).
Another possibility is that both Homo habilis and H. ergaster both evolved from a common ancestor around 2.3 million years ago. Spoor et al (2007) note that both species were sympatric in the Turkana Basin for approximately 400,000 years. They believe that this is a more likely explanation than the alternative, which is a Homo ergaster split from an earlier population of Homo habilis, with the Turkana Basin being a region of secondary contact between the two species. Cameron and Groves (2004) take the opposite view, pointing out that Homo ergaster does not appear in the fossil record until much later than Homo habilis.
If the second scenario is correct, and Homo ergaster split in a sudden “punctuated” evolutionary event, a possible cause would be the increase in seasonal rainfall and aridity that occurred across Africa with the onset of the Pleistocene, 1.8 million years ago.
On the other hand it is possible that from 3 to 2 million years ago in Africa there existed a “bush” or complex of closely-related but distinct hominin species, and that Homo habilis and H. ergaster could have emerged from totally separate branches. If this is correct, then there are still many species of hominin remaining undiscovered.
Relationship to Homo erectus:
It used to be the general view that the “Version 2.0 humans” living in Africa and Europe until 600,000 years ago and Asia until possibly 50,000-30,000 years ago belonged to a single species, Homo erectus. But this view has fallen out of fashion. On average, the African skulls tend to be higher-domed and thinner-walled than those from East Asia, and they have less massive faces and brow-ridges. Accordingly the African hominins are usually now classified as Homo ergaster, with the designation H. erectus reserved for Asian fossils. Many sources do still lump both together as Homo erectus or use the term “African Homo erectus” in preference to H. ergaster.
The view that Homo ergaster left Africa and evolved into Homo erectus, while Africa remained exclusively populated by stay-at-home H. ergaster, is almost certainly an oversimplification.
The presence of the 1.95-1.77 million years old ergaster-like skulls at Dmanisi show that humans had left Africa by then, but whether or not these hominins can be included in Homo ergaster or were ancestral the Homo erectus in Asia remains a matter for debate.
The discovery of an erectus-like hominin at Ceprano, Italy, in 1994 and its similarity to the Olduvai hominin OH 9 (Clarke, 2000) has led to the view that there was a migration back into Africa by Homo erectus. In addition to OH 9, the more recent OH 12, the “Daka Cranium” (BOU-VP 2/66), from Bouri and the similar cranium from Buia have been proposed as examples of “Into Africa” Homo erectus rather than Homo ergaster (Cameron & Groves, 2004). The partial skullcap OH 9 has massive brow-ridges, thick walls and angular rear profile typical of East Asian Homo erectus, but in other characteristics it is like Homo ergaster. The Buia and Daka skulls show only minor differences from earlier Homo ergaster (Scarre, 2005).
Berhane Asfaw argues that “the Daka cranium confirms previous suggestions that geographic subdivision of early H. erectus into separate species lineages is biologically misleading, artificially inflating early Pleistocene species diversity. Rather, the Daka calvaria is consistent with the hypothesis of a widespread, moderately polymorphic and polytypic species [i.e. Homo erectus] at 1.0Myr” Asfaw et al (2002).
Subsequent evolutionary career:
The traditional view is that around 600,000 years ago, Homo ergaster (or African Homo erectus) evolved into the larger-brained “archaic Homo sapiens” from which two distinct subspecies, the Neanderthals and modern Homo sapiens (us), eventually arose. The currently popular view represents only a slight updating of this paradigm in that “archaic Homo sapiens” is now seen as a distinct species, Homo heidelbergensis. This species migrated into Europe, where it evolved into Homo neanderthalensis (the Neanderthals). Meanwhile, H. heidelbergensis in Africa evolved into Homo sapiens about 200,000 years ago. While it does seem likely that African Homo erectus (whatever this may be) did evolve into larger-brained hominins it is problematic as to whether there was just one successor species or several; from which of these Homo sapiens eventually arose; of if indeed the progenitor species for Homo sapiens was African or a European species that migrated back into Africa.
Technology:
The earliest Homo ergaster remains, including the Dmanisi hominins, are associated with the Oldowan (Mode I) tool tradition. At about 1.65 million years ago these primitive tools give way to the teardrop shaped “hand-axes” of the Acheulian (Mode II) tradition, named for Saint-Acheul in Northern France, where the first examples were found at in the mid-19th Century. The oldest known Acheulian tools are dated to 1.65 million years ago from West Turkana, Kenya and 1.5-1.4 million years ago from Konso, Ethiopia, East Turkana, Kenya and Peninj, near Olduvai Gorge, Tanzania (Scarre, 2005).
The Acheulian hand-axe tradition endured with little change until it was finally abandoned 250,000 years ago. It has been described as displaying a “variable sameness” that strikes “even enthusiasts as monotonous”. The tradition does however represent a considerable advance on its predecessor as it is necessary for the maker to preconceive the form of the finished tool from a block of raw material. The 3D symmetry often shown by the axes indicate their makers were intent on imposing form on the artefact rather than just creating a sharp edge as in the Oldowan tradition. This is very difficult and requires forward planning (Mithen, 1996).
Despite the name, the function of these often beautifully-crafted hand-axes remains conjectural. At some sites such as Melka Kunture in Ethiopia, Olorgesailie in Kenya, Isimila in Tanzania and Kalambo Falls, hand-axes occur in large numbers and appear to have been discarded soon after manufacture, with no sign of wear, suggesting that they were never used. Another major puzzle is that they are often too large to be useful (see, for example, the fine example in the Natural History Museum in Kensington).
One theory (Kohn & Mithen, 1999) proposes that the axes were made to impress prospective mates. When a female saw a large, symmetrical axe, she might conclude that its maker possessed the right attributes to father successful offspring. The axe, having served its purpose (or not) would then be discarded. This – like the elaborate bower of the male bower bird – would be an example of the extended phenotype of a species playing a role in sexual selection (Dawkins, 1982).
Regardless of whether or not the mate selection hypothesis is true, the hand-axes almost certainly were used as tools. Experiments have shown them to be effective for butchery purposes; some may have been used as a discus for bringing down prey; others could have been used for chopping and scraping wood. Klein and Edgar (2002) liken the Acheulian hand-axe to a Swiss army knife.
Another issue with the hand-axes is that while they are ubiquitous in Africa and western Eurasia, they are not found east of Northern India. This was first noted by American archaeologist Hallam Movius in 1948. The “Movius Line” has stood the test of time and two theories have been proposed to explain it. One is that the ancestors of those living east of the Movius Line left Africa before the hand-axes were invented. The other possibility is that the migrants from Africa passed through a region lacking suitable materials to make the axes, and by the time they emerged from it, the tradition had been forgotten.
Recent discoveries support the first possibility. Hominin remains such as the Mojokarta Child [Homo erectus] from Java have now been dated to 1.81 million years ago and the Dmanisi hominins are at least 1.77 million years old, predating the earliest-known Acheulian hand-axes.
References:
Berhane Asfaw, W. Henry Gilbert, Yonas Beyene, William K. Hart,
Paul R. Rennek, Giday WoldeGabriel, Elisabeth S. Vrba & Tim D. White (2002): Remains of Homo erectus from Bouri, Middle Awash, Ethiopia, Nature Vol. 416, 21 March 2002.
A. Ascenzi, F. Mallegni, G. Manzi, A. G. Segre & E. Segre Naldini (2000): A re-appraisal of Ceprano calvaria affinities with Homo erectus, after the new reconstruction, Journal of Human Evolution (2000) 39, 443–450.
Cameron D & Groves C (2004): Bones, Stones and Molecules: “Out of Africa” and Human Origins, Elsevier Academic Press.
Clarke R.J (2000): A corrected reconstruction and interpretation of the Homo erectus calvaria from Ceprano, Italy, Journal of Human Evolution, Volume 39, Number 4, October 2000, pp. 433-442.
Conroy G (1997): “Reconstructing Human Origins: A Modern Synthesis”, W.W. Norton & Co. Inc, New York, NY & London.
Dawkins R (1982): “The Extended Phenotype”, Oxford University Press.
Klein, R. (1999): The Human Career (2nd Edition), University of Chicago Press.
Klein R & Edgar B (2002): “The Dawn of Human Culture”, John Wiley & Sons Inc., New York.
Kohn M & Mithen S (1999): “Handaxes: products of sexual selection?” Antiquity 73: 518-526.
Lewin, R and Foley, R 2004: Principles of Human Evolution (2nd edition), Blackwell Science Ltd.
Manzi G (2004): Human Evolution at the Matuyama-Brunhes
Boundary, Evolutionary Anthropology 13:11–24 (2004)
G. Manzi, F. Mallegni, and A. Ascenzi (2001): A cranium for the earliest Europeans: Phylogenetic position of the hominid from Ceprano, Italy, PNAS August 14, 2001 vol. 98 no. 17 10013.
Mithen S (1996): “The Prehistory of the Mind”, Thames & Hudson.
Scarre C (2005) (Ed): “The human past”, Thames & Hudson.
F. Spoor, M. G. Leakey, P. N. Gathogo, F. H. Brown, S. C. Anton, I. McDougall, C. Kiarie, F. K. Manthi & L. N. Leakey (2007): Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya, Nature Vol 448 9 August 2007.
Gen Suwa, Berhane Asfaw, Yohannes Haile-Selassie, Tim White, Shigehiro Katoh, Giday WoldeGabriel, William K. Hart, Hideo Nakaya, Yonas Beyene (2007): Early Pleistocene Homo erectus fossils from Konso, southern Ethiopia, Anthropological Science, Vol. 115, 133–151, 2007.
© Christopher Seddon 2009
Sunday, 11 January 2009
Java Man and Peking Man (Homo erectus)
Java Man is the popular name given to the fossil hominin discovered in 1891 by Eugene Dubois at the village of Trinil, on the banks of the Solo River in eastern Java. The find consisted of a skullcap and a femur. It is uncertain if are from the same individual and the femur is believed by some to be from a modern human. Dubois initially named his find Anthropithecus erectus (“Upright man-ape”, suggesting it was more ape-like than human) then he renamed it Pithecanthropus erectus (“Upright ape-man”, suggesting closer human affinities).
Peking Man is the popular name given to the fossil hominins discovered in the 1920s and 1930s at Zhoukoudian, near Beijing and described as Sinanthropus pekinensis by Davidson Black.
In 1944 both species were reclassified as Homo erectus by the late Ernst Mayr as part of a general tidying-up exercise of the bewildering plethora of hominin genera and species then recognised.
Eugene Dubois (1858-1940) was a Dutch anatomist who became fascinated with the subject of human origins. He had been an avid fossil-collector from childhood and believed that fossils provided the best way of elucidating evolutionary history, an approach which was not universally accepted at the time.
Dubois became convinced that the best place to search for the fossil origins of mankind would be the tropics, and to this end he joined the Dutch army as a doctor and had himself posted to the Dutch East Indies, arriving in Sumatra in December 1887. The demands of his day job meant it was quite a while before he could begin his search of the many caves in Sumatra, where he believed the fossil evidence would be found. Eventually, though, he was able to investigate the caves at Lida Adjer and duly began to unearth the bones of various mammals. Armed with this evidence, he managed to persuade the Dutch government to relieve him of his medical duties and allow him work full time on his fossil-hunting. He was also assigned the services of fifty convicts to help him with his excavations.
After failing to discover any human fossils in Sumatra, Dubois received permission in April 1890 to transfer his work to neighbouring Java. He began searching cave sites, but again without success, so he began investigating open sites as well. Finally he was rewarded with success and in October 1891, at Trinil, he recovered a low-domed angular thick-walled human skullcap with a large shelf-like brow ridge. In August 1892 he recovered a humanlike femur from what he believed to be the same site.
Convinced he had found the “missing link” – a transitional form between humans and apes, Dubois at first proposed the name Anthropithecus erectus based on what he believed were the ape-like proportions of its brain - which he estimated at 700cc - and the modernity of the femur. However in November 1892 he revised the cranial capacity upwards to 900cc, closer to that of a modern human than an ape. Accordingly he renamed the fossil Pithecanthropus erectus.
In 1895 Dubois returned to Europe and embarked on a tour to promote his claim to have found the missing link. Although the scientific community were intrigued by his discoveries, his conclusions were generally rejected. Disappointed, he eventually accepted a position as professor of geology at the University of Amsterdam and refused to allow any examination of his fossils until, under increasing pressure to grant access, he finally relented in 1923. His motives have been questioned: the popular view is that he was acting out of spite, like an angry schoolboy taking his ball and going home. However it is more likely that he was protecting his intellectual property. In 1897 he had permitted Gustav Schwalbe of the University of Strasburg to make a cast of the skullcap: Schwalbe had then produced a monograph that had been far more sympathetically received than any of Dubois’ own work.
By the 1920s and 1930s further hominin fossils were coming to light. In 1927 the Canadian anthropologist Davidson Black described Sinanthropus pekinensis (“Chinese man of Peking” [Beijing]), based on an examination of two teeth recovered from the cave site of Zhoukoudian in Dragon Bone Hill, near Beijing. The find became popularly known as Peking Man. Several skullcaps were recovered from the same site in subsequent years. Both Black and anatomist Franz Weidenreich noted similarities between the Zhoukoudian finds and Pithanthropus, but Dubois rejected the similarities.
Unfortunately the Zhoukoudian fossils were lost during World War II. Work at the site was halted by the Japanese invasion in 1937, but the fossils remained at the Cenozoic Research Laboratory of the Peking Union Medical College until 1941, when an attempt was made to transfer them to the United States for safekeeping. They were never seen again. It is thought that they were in possession of a group of US marines, who were captured when war broke out between Japan and the USA. Fortunately Weidenreich had made plaster casts, now in the American Museum of Natural History, New York. After the war, excavation resumed at Zhoukoudian and a number of discoveries have been made since, including two skull fragments. Zhoukoudian became a World Heritage site in 1987.
In 1936 palaeontologist Ralph von Koenigswald made a further discovery on Java itself. Excavating near Mojokerto, eastern Java, in 1936, von Koenigswald recovered a juvenile skull now known as the Mojokerto Child, who was anything from 2 to 6 years old at death, but again Dubois rejected any affinities to Pithecanthropus. The following year, von Koenigswald made further discoveries at Sangiran, East-Central Java with the aid of local people, who he promised to pay 10 cents for each find. The finds included fragments making up an almost-complete skull, though von Koenigswald’s delight at this discovery was somewhat tempered when he learned his helpers were breaking larger finds into smaller pieces to maximise their bounty!
Dubois argued his find was more ape-like than the later discoveries, leading to the popular misconception that he had repudiated his claim that it was an intermediate form. Eugene Dubois died in December 1940, having done himself few favours in the last four decades of his life. British anthropologist Sir Arthur Keith, writing in an obituary notice, observed that Dubois was “an idealist who held his ideas so firmly that he tended to bend the facts rather than alter his ideas to fit them.”
It is now generally accepted that the Javanese and Chinese hominins belong to the same or closely-related species, usually classed as Homo erectus. Some authorities recognise a separate species, Homo pekinensis, for the Chinese hominins.
Dating the Javanese fossils using modern argon-40/argon-39 and potassium/argon dating techniques of volcanic material recovered from the same context as the fossils has been problematic. This is due to deformation and distortion by earth movements of the stratigraphic beds with which the fossils are associated. Another problem has been uncertainty regarding the exact discovery sites, which were less scrupulously recorded than would now be the case. Dates ranging from as recent as 1.0 million to as long ago as 1.65 million have been proposed. Dates of 1.81 million years for the Mojokarto Child and 1.66 million years for the Sangiran fossil were reported in 1994 (Swisher et al, 1994).
Homo erectus (or pekinensis) fossils from Zhoukoudian and elsewhere in China have been dated to between 800,000 and 400,000 years old by palaeomagnetic and biostratigraphic techniques. However stone tools from the Nihewan Basin, 150km (90 miles) west of Beijing have been dated to as far back as 1.6 million years old, implying a much earlier arrival.
References:
Curtis G, Swisher C & Lewin R (2000): Java Man, Scribner, USA.
Klein R (1999): "The Human Career", 2nd edition, University of Chicago Press
Scarre C (2005) (Ed): “The human past”, Thames & Hudson.
CC Swisher 3rd, GH Curtis, T Jacob, AG Getty, A Suprijo and Widiasmoro (1994): Age of the earliest known hominids in Java, Indonesia, Science, Vol. 263, Issue 5150, 1118-1121, 25 February 1994.
© Christopher Seddon 2009
Peking Man is the popular name given to the fossil hominins discovered in the 1920s and 1930s at Zhoukoudian, near Beijing and described as Sinanthropus pekinensis by Davidson Black.
In 1944 both species were reclassified as Homo erectus by the late Ernst Mayr as part of a general tidying-up exercise of the bewildering plethora of hominin genera and species then recognised.
Eugene Dubois (1858-1940) was a Dutch anatomist who became fascinated with the subject of human origins. He had been an avid fossil-collector from childhood and believed that fossils provided the best way of elucidating evolutionary history, an approach which was not universally accepted at the time.
Dubois became convinced that the best place to search for the fossil origins of mankind would be the tropics, and to this end he joined the Dutch army as a doctor and had himself posted to the Dutch East Indies, arriving in Sumatra in December 1887. The demands of his day job meant it was quite a while before he could begin his search of the many caves in Sumatra, where he believed the fossil evidence would be found. Eventually, though, he was able to investigate the caves at Lida Adjer and duly began to unearth the bones of various mammals. Armed with this evidence, he managed to persuade the Dutch government to relieve him of his medical duties and allow him work full time on his fossil-hunting. He was also assigned the services of fifty convicts to help him with his excavations.
After failing to discover any human fossils in Sumatra, Dubois received permission in April 1890 to transfer his work to neighbouring Java. He began searching cave sites, but again without success, so he began investigating open sites as well. Finally he was rewarded with success and in October 1891, at Trinil, he recovered a low-domed angular thick-walled human skullcap with a large shelf-like brow ridge. In August 1892 he recovered a humanlike femur from what he believed to be the same site.
Convinced he had found the “missing link” – a transitional form between humans and apes, Dubois at first proposed the name Anthropithecus erectus based on what he believed were the ape-like proportions of its brain - which he estimated at 700cc - and the modernity of the femur. However in November 1892 he revised the cranial capacity upwards to 900cc, closer to that of a modern human than an ape. Accordingly he renamed the fossil Pithecanthropus erectus.
In 1895 Dubois returned to Europe and embarked on a tour to promote his claim to have found the missing link. Although the scientific community were intrigued by his discoveries, his conclusions were generally rejected. Disappointed, he eventually accepted a position as professor of geology at the University of Amsterdam and refused to allow any examination of his fossils until, under increasing pressure to grant access, he finally relented in 1923. His motives have been questioned: the popular view is that he was acting out of spite, like an angry schoolboy taking his ball and going home. However it is more likely that he was protecting his intellectual property. In 1897 he had permitted Gustav Schwalbe of the University of Strasburg to make a cast of the skullcap: Schwalbe had then produced a monograph that had been far more sympathetically received than any of Dubois’ own work.
By the 1920s and 1930s further hominin fossils were coming to light. In 1927 the Canadian anthropologist Davidson Black described Sinanthropus pekinensis (“Chinese man of Peking” [Beijing]), based on an examination of two teeth recovered from the cave site of Zhoukoudian in Dragon Bone Hill, near Beijing. The find became popularly known as Peking Man. Several skullcaps were recovered from the same site in subsequent years. Both Black and anatomist Franz Weidenreich noted similarities between the Zhoukoudian finds and Pithanthropus, but Dubois rejected the similarities.
Unfortunately the Zhoukoudian fossils were lost during World War II. Work at the site was halted by the Japanese invasion in 1937, but the fossils remained at the Cenozoic Research Laboratory of the Peking Union Medical College until 1941, when an attempt was made to transfer them to the United States for safekeeping. They were never seen again. It is thought that they were in possession of a group of US marines, who were captured when war broke out between Japan and the USA. Fortunately Weidenreich had made plaster casts, now in the American Museum of Natural History, New York. After the war, excavation resumed at Zhoukoudian and a number of discoveries have been made since, including two skull fragments. Zhoukoudian became a World Heritage site in 1987.
In 1936 palaeontologist Ralph von Koenigswald made a further discovery on Java itself. Excavating near Mojokerto, eastern Java, in 1936, von Koenigswald recovered a juvenile skull now known as the Mojokerto Child, who was anything from 2 to 6 years old at death, but again Dubois rejected any affinities to Pithecanthropus. The following year, von Koenigswald made further discoveries at Sangiran, East-Central Java with the aid of local people, who he promised to pay 10 cents for each find. The finds included fragments making up an almost-complete skull, though von Koenigswald’s delight at this discovery was somewhat tempered when he learned his helpers were breaking larger finds into smaller pieces to maximise their bounty!
Dubois argued his find was more ape-like than the later discoveries, leading to the popular misconception that he had repudiated his claim that it was an intermediate form. Eugene Dubois died in December 1940, having done himself few favours in the last four decades of his life. British anthropologist Sir Arthur Keith, writing in an obituary notice, observed that Dubois was “an idealist who held his ideas so firmly that he tended to bend the facts rather than alter his ideas to fit them.”
It is now generally accepted that the Javanese and Chinese hominins belong to the same or closely-related species, usually classed as Homo erectus. Some authorities recognise a separate species, Homo pekinensis, for the Chinese hominins.
Dating the Javanese fossils using modern argon-40/argon-39 and potassium/argon dating techniques of volcanic material recovered from the same context as the fossils has been problematic. This is due to deformation and distortion by earth movements of the stratigraphic beds with which the fossils are associated. Another problem has been uncertainty regarding the exact discovery sites, which were less scrupulously recorded than would now be the case. Dates ranging from as recent as 1.0 million to as long ago as 1.65 million have been proposed. Dates of 1.81 million years for the Mojokarto Child and 1.66 million years for the Sangiran fossil were reported in 1994 (Swisher et al, 1994).
Homo erectus (or pekinensis) fossils from Zhoukoudian and elsewhere in China have been dated to between 800,000 and 400,000 years old by palaeomagnetic and biostratigraphic techniques. However stone tools from the Nihewan Basin, 150km (90 miles) west of Beijing have been dated to as far back as 1.6 million years old, implying a much earlier arrival.
References:
Curtis G, Swisher C & Lewin R (2000): Java Man, Scribner, USA.
Klein R (1999): "The Human Career", 2nd edition, University of Chicago Press
Scarre C (2005) (Ed): “The human past”, Thames & Hudson.
CC Swisher 3rd, GH Curtis, T Jacob, AG Getty, A Suprijo and Widiasmoro (1994): Age of the earliest known hominids in Java, Indonesia, Science, Vol. 263, Issue 5150, 1118-1121, 25 February 1994.
© Christopher Seddon 2009
Saturday, 10 January 2009
Homo floresiensis
Homo floresiensis is the name given to a possible human species that lived on the Indonesian island of Flores. One largely complete skeleton (LB1) and a complete mandible (LB2) were found in sediment in the Liang Bua Cave in eastern Flores, in 2003 (Brown et al, 2004). The material, dated at 18,000 years old, was not fossilised or covered with calcium carbonate, but was extremely fragile. The discoverers, a team led by anthropologists Peter Brown and Michael Morwood, recovered further material including a second mandible and postcranial material from other individuals, in 2004. In total, the finds represented at least nine individuals. Stone tools were also found, dating to 95,000-75000 years old and 12,000 years old. These comprised high densities of stone cores, flaking debris, retouched tools and anvils, evidencing a flaking technology comparable to that found at African Oldowan and other Lower Palaeolithic sites. The tools were accompanied by faunal remains, indicating that the area was a focus for a range of hominin activities (Morwood et al, 2005; Tocheri et al, 2007).
LB1 was claimed to have been a 30-year-old female. The cranial capacity of LB1 is 380cc and its stature is no more than 3ft6 (106cm), both of which are comparable to or smaller than Australopithecus afarensis (“Lucy”). The discoverers argued, however, that it possessed a variety of both primitive and derived features, and should be placed in genus Homo:
“When considered as a whole, the cranial and postcranial skeleton of LB1 combines a mosaic of primitive, unique and derived features not recorded for any other hominin. Although LB1 has the small endocranial volume and stature evident in early australopithecines, it does not have the great postcanine tooth size, deep and prognathic facial skeleton, and masticatory adaptations common to members of this genus. Instead, the facial and dental proportions, postcranial anatomy consistent with human-like obligate bipedalism and a masticatory apparatus most similar in relative size and function to modern humans all support assignment to the genus Homo—as does the inferred phylogenetic history, which includes endemic dwarfing of H. erectus. For these reasons, we argue that LB1 is best placed in this genus and have named it accordingly.” (Brown et al, 2004).
The diminutive size of Homo floresiensis was, the team claimed, a result of a phenomenon known as insular dwarfism, where animals living on an island where food is relatively scarce and predators are few or absent will “downsize” over many generations in order to reduce calorific requirements. This is of course no more than evolution favouring the smaller offspring in each generation. If predators do not pose a threat, any advantages in being large will be outweighed by poorer fuel-economy. Before Mesolithic humans reached Flores, the island met both conditions in being both relatively faunally-impoverished and lacking any predators other than the Komodo dragon. If early humans such as Homo erectus had reached Flores, then the same thing could have happened, leading to H. floresiensis.
The team claimed that despite its tiny ape-like brain, the encephalization quotient (EQ) or brain to mass ratio was in the range 2.5 to 4.6, compared with 5.8 to 8.1 for modern humans, 3.3 to 4.4 for Homo erectus/ergaster and 3.6 to 4.3 for Homo habilis. The figure was derived from an estimated brain mass of 433.2gm (based on cranial volume) and two estimates of body mass: an estimate based on stature of 106cm gave 16.0-28.7kg; one based on femur cross-sectional area of 525mm2 gave 36kg.
The EQ is a better indication of intelligence than absolute brain size; for example, elephants and whales have larger brains than humans, but are generally considered to be less intelligent than the latter. The team claimed the higher figure of 4.6 was supported by the probability that Homo floresiensis would have the same lean, narrow body shape as a modern Old World tropical-dwelling human. Thus H. floresiensis was capable of complex behaviour and cognition, and was probably the maker of the tools. Oldowan-equivalent technology would be well within its capabilities.
The discovery attracted considerable publicity, and Homo floresiensis was immediately nicknamed the Flores Hobbit, to Brown’s considerable annoyance (quoted in the Observer, 31 October 2004). However doubts as to whether it was genuinely a new human species emerged almost immediately.
The Indonesian anthropologist Prof. Teuku Jacob claimed that LB1 was a modern human suffering from microcephaly, a developmental disorder leading to a smaller brain. Jacob claimed LB1 was a male Homo sapiens aged 25-30 of Australomelanesian extraction.
An unpleasant dispute then followed when, in December 2004, Jacob removed most of the remains from the Jakarta's National Research Centre of Archaeology, where they had been placed for safekeeping, without permission of this institution’s directors. Jacob was widely cited in press reports as having a reputation for preventing access to specimens in his keeping and Brown was quoted in the New Zealand Herald as saying he doubted “if the material will ever be studied again”.
Jacob eventually did return the remains, but the discoverers claimed the bones were extensively damaged in Jacob's lab during attempts to make casts. The alleged damage included long, deep cuts marking the lower edge of the LB1's jaw on both sides, said to be caused by a knife used to cut away the rubber mould. In addition, LB2 was snapped and glued back together. Whoever was responsible misaligned the pieces and put them at an incorrect angle. The pelvis of LB1 was smashed, destroying details that reveal body shape, gait and evolutionary history. Morwood accused Jacob of being greedy and acting irresponsibly. Jacob denied any wrongdoing and published his own findings contra Brown et al in July 2006 (Jacob et al, 2006). Teuku Jacob died in October 2007, aged 77, but his death did not put an end to the controversy.
Although primatologist Robert Martin of the Field Museum, Chicago, IL supported Jacob’s position (Martin et al, 2006), the majority of workers rejected the microcephaly theory and accepted Homo floresiensis as a new human species (e.g. Argue et al, 2006; Falk et al, 2005 & 2007; Lyras et al, 2008 and Tocheri et al, 2007) .
The studies mainly focussed on the cranial and post-cranial metrics of LB1 in comparison to microcephalic humans, pygmies, early human species (Homo erectus, H. ergaster, H. habilis, etc) and australopithecines (A. garhi, A. africanus, P. bosei, etc.). The general conclusion was that H. floresiensis showed a better fit with the various extinct hominins than it did with the microcephalic or normal modern humans, though the studies differed as to its likely phylogeny, with affinities to Homo erectus, Homo habilis and even the later australopithecines all being proposed. LB1’s long low cranial vault is not a feature shared with modern humans, microcephalic or not (Lyras et al, 2008); LB1’s wrist morphology, based on three wrist bones, predates that of modern humans (Tocheri et al, 2007). Other pathological explanations such as Laron syndrome and cretinism were also rejected (Lyras et al, 2008).
Falk et al (2005) noted expansions in the frontal polar region of LB1. This part of the prefrontal cortex in humans and apes consists of Brodmann’s area 10 (BA10), which in humans may be involved in higher cognitive processes such as the undertaking of initiatives and the planning of future activities. The Falk study concluded that LB1’s brain could not have been a miniaturized version of Homo sapiens or H. erectus.
Citing this study, Argue et al (2006) suggested the implication is that LB1 possessed developed cognitive abilities and was able to plan, respond to conditions, use memories, and transfer information between group members.
Brumm et al (2006) considered 880,000 year old artefacts recovered from the Mata Menge site at the Soa Basin, central Flores in comparison to the Liang Bua artefacts and suggested the two show technological continuity. They suggest the hominins responsible for the Liang Bua artefacts were also responsible for those at Mata Menge, though no hominin remains have been recovered from the latter site.
What are we to make of all this? The case for Homo floresiensis being a pathological modern human does not strike me as being very convincing and on the balance of probabilities I would cautiously accept that it is indeed a new species of hominin. Obviously further evidence, in particular evidence that can be tied to the earlier tool finds, would be highly desirable.
Could H. floresiensis be an intermediate between early Homo and late Australopithecus that migrated out of Africa prior to 2 million years ago (Argue et al, 2006)? It’s not impossible that enhanced cognitive function evolved more than once, in Homo habilis and its descendants and in Homo floresiensis (though the latter would have to be transferred to a new genus to avoid paraphyly should this hypothesis become accepted). Nor would it be impossible for such a hominin to diffuse from Africa, given that the ancestors of the orang-utans did millions of years earlier. The main problem is there is absolutely no other evidence supporting dispersal from Africa of any australopithecine species or of Homo habilis, or of anything intermediate between the two. Homo georgicus, the small-brained hominin from Dmanisi, Georgia, has been touted as evidence Homo habilis did migrate from Africa, but it has now been shown to have a derived Homo ergaster (African Homo erectus) body plan.
Early Homo erectus, or something of that grade seems a more plausible ancestor. The tool technology is consistent with that of the first H. erectus dispersal from Africa, which seems to have happened before the invention of the later Mode II Acheulian hand-axe tradition. The cognitive abilities of Homo floresiensis were probably commensurate with such technology, which predates the emergence of modern human behaviour. As such, therefore, H. floresiensis would have lacked the complex language of modern humans, though it probably had language of sorts.
The question of how the forbears of these people reached Flores in the first place has led some to speculate that they must had the ability to build boats, since Flores – unlike many islands in the Indonesian archipelago – was never connected to the mainland, even during the maximum extent of the ices ages, when sea-levels dropped. But they could have been swept out to sea and stranded there by a natural occurrence such as a flash-flood or a tsunami, possibly on a raft of matted vegetation. This is believed to have been the way the ancestors of the New World monkeys reached South America from Africa; nobody is suggesting that they built boats!
Probably the most controversial idea is that Homo floresiensis survived into modern times and is the mythological Ebu Gogo said to have been living on Flores when the Portuguese arrived 400 years ago, and some claim were still being seen as recently as 100 years ago; and that similar people are the basis of similar legends such as the Orang Pendek from Sumatra and even leprechauns in Ireland?
I will admit to being sceptical (decidedly so about leprechauns!), if only because “little people” are so prevalent in world folk traditions that if these were due to actual diminutive hominins, concrete evidence would have emerged by now. However if an endemic dwarf hominin species can arise on Flores, there is certainly no reason to suppose similar species could not arise elsewhere and it is quite possible that evidence from similar genetically-isolated locations might come to light in the future.
References:
Debbie Argue, Denise Donlon, Colin Groves, Richard Wright (2006): Homo floresiensis: Microcephalic, pygmoid, Australopithecus, or Homo? Journal of Human Evolution 51 (2006) 360-374.
P. Brown, T. Sutikna, M. J. Morwood, R. P. Soejono, Jatmiko, E. Wayhu Saptomo & Rokus Awe Due (2004): A new small-bodied hominin from the
Late Pleistocene of Flores, Indonesia, Nature Vol. 431 28 October 2004.
Adam Brumm, Fachroel Aziz, Gert D. van den Bergh, Michael J. Morwood, Mark W. Moore, Iwan Kurniawan, Douglas R. Hobbs & Richard Fullagar (2006): Early stone technology on Flores and its implications for Homo floresiensis, Nature Vol. 441 1 June 2006.
Dean Falk, Charles Hildebolt, Kirk Smith, M. J. Morwood, Thomas Sutikna, Peter Brown, Jatmiko, E. Wayhu Saptomo, Barry Brunsden, Fred Prior (2005): The Brain of LB1, Homo floresiensis, Science Vol. 308 8 April 2005.
Dean Falk, Charles Hildebolt, Kirk Smith, M. J. Morwood, Thomas Sutikna, Jatmiko, E. Wayhu Saptomo, Herwig Imhof, Horst Seidler and Fred Prior (2007): Brain shape in human microcephalics and Homo floresiensis, PNAS February 13, 2007 vol. 104 no. 7 2513–2518.
T. Jacob, E. Indriati, R. P. Soejono, K. Hsu, D. W. Frayer, R. B. Eckhardt, A. J. Kuperavage, A. Thorne and M. Henneberg (2006): Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities, PNAS September 5, 2006 vol. 103 no. 36 13421–13426.
G.A. Lyras, M.D. Dermitzakis, A.A.E. Van der Geer, S.B. Van der Geer, J. De Vos (2008): The origin of Homo floresiensis and its relation to evolutionary
processes under isolation, Anthropological Science, 1 August 2008.
R. D. Martin, A. M. MacLarnon, J. L. Phillips, L. Dussubieux,
P. R. Williams, W. B. Dobyns (2006): Comment on ‘‘The Brain of LB1,
Homo floresiensis’’, Science 19 May 2006 Vol. 312.
M. J. Morwood, P. Brown, Jatmiko, T. Sutikna, E. Wahyu Saptomo, K. E. Westaway, Rokus Awe Due, R. G. Roberts, T. Maeda, S. Wasisto & T. Djubiantono (2005): Further evidence for small-bodied hominins from
the Late Pleistocene of Flores, Indonesia, Nature Vol. 437 13 October 2005.
Scarre C (2005) (Ed): “The human past”, Thames & Hudson.
Matthew W. Tocheri, Caley M. Orr, Susan G. Larson, Thomas Sutikna,
Jatmiko, E. Wahyu Saptomo, Rokus Awe Due, Tony Djubiantono,
Michael J. Morwood, William L. Jungers (2007): The Primitive Wrist of Homo floresiensis and Its Implications for Hominin Evolution, Science Vol. 317 21 September 2007.
© Christopher Seddon 2009
LB1 was claimed to have been a 30-year-old female. The cranial capacity of LB1 is 380cc and its stature is no more than 3ft6 (106cm), both of which are comparable to or smaller than Australopithecus afarensis (“Lucy”). The discoverers argued, however, that it possessed a variety of both primitive and derived features, and should be placed in genus Homo:
“When considered as a whole, the cranial and postcranial skeleton of LB1 combines a mosaic of primitive, unique and derived features not recorded for any other hominin. Although LB1 has the small endocranial volume and stature evident in early australopithecines, it does not have the great postcanine tooth size, deep and prognathic facial skeleton, and masticatory adaptations common to members of this genus. Instead, the facial and dental proportions, postcranial anatomy consistent with human-like obligate bipedalism and a masticatory apparatus most similar in relative size and function to modern humans all support assignment to the genus Homo—as does the inferred phylogenetic history, which includes endemic dwarfing of H. erectus. For these reasons, we argue that LB1 is best placed in this genus and have named it accordingly.” (Brown et al, 2004).
The diminutive size of Homo floresiensis was, the team claimed, a result of a phenomenon known as insular dwarfism, where animals living on an island where food is relatively scarce and predators are few or absent will “downsize” over many generations in order to reduce calorific requirements. This is of course no more than evolution favouring the smaller offspring in each generation. If predators do not pose a threat, any advantages in being large will be outweighed by poorer fuel-economy. Before Mesolithic humans reached Flores, the island met both conditions in being both relatively faunally-impoverished and lacking any predators other than the Komodo dragon. If early humans such as Homo erectus had reached Flores, then the same thing could have happened, leading to H. floresiensis.
The team claimed that despite its tiny ape-like brain, the encephalization quotient (EQ) or brain to mass ratio was in the range 2.5 to 4.6, compared with 5.8 to 8.1 for modern humans, 3.3 to 4.4 for Homo erectus/ergaster and 3.6 to 4.3 for Homo habilis. The figure was derived from an estimated brain mass of 433.2gm (based on cranial volume) and two estimates of body mass: an estimate based on stature of 106cm gave 16.0-28.7kg; one based on femur cross-sectional area of 525mm2 gave 36kg.
The EQ is a better indication of intelligence than absolute brain size; for example, elephants and whales have larger brains than humans, but are generally considered to be less intelligent than the latter. The team claimed the higher figure of 4.6 was supported by the probability that Homo floresiensis would have the same lean, narrow body shape as a modern Old World tropical-dwelling human. Thus H. floresiensis was capable of complex behaviour and cognition, and was probably the maker of the tools. Oldowan-equivalent technology would be well within its capabilities.
The discovery attracted considerable publicity, and Homo floresiensis was immediately nicknamed the Flores Hobbit, to Brown’s considerable annoyance (quoted in the Observer, 31 October 2004). However doubts as to whether it was genuinely a new human species emerged almost immediately.
The Indonesian anthropologist Prof. Teuku Jacob claimed that LB1 was a modern human suffering from microcephaly, a developmental disorder leading to a smaller brain. Jacob claimed LB1 was a male Homo sapiens aged 25-30 of Australomelanesian extraction.
An unpleasant dispute then followed when, in December 2004, Jacob removed most of the remains from the Jakarta's National Research Centre of Archaeology, where they had been placed for safekeeping, without permission of this institution’s directors. Jacob was widely cited in press reports as having a reputation for preventing access to specimens in his keeping and Brown was quoted in the New Zealand Herald as saying he doubted “if the material will ever be studied again”.
Jacob eventually did return the remains, but the discoverers claimed the bones were extensively damaged in Jacob's lab during attempts to make casts. The alleged damage included long, deep cuts marking the lower edge of the LB1's jaw on both sides, said to be caused by a knife used to cut away the rubber mould. In addition, LB2 was snapped and glued back together. Whoever was responsible misaligned the pieces and put them at an incorrect angle. The pelvis of LB1 was smashed, destroying details that reveal body shape, gait and evolutionary history. Morwood accused Jacob of being greedy and acting irresponsibly. Jacob denied any wrongdoing and published his own findings contra Brown et al in July 2006 (Jacob et al, 2006). Teuku Jacob died in October 2007, aged 77, but his death did not put an end to the controversy.
Although primatologist Robert Martin of the Field Museum, Chicago, IL supported Jacob’s position (Martin et al, 2006), the majority of workers rejected the microcephaly theory and accepted Homo floresiensis as a new human species (e.g. Argue et al, 2006; Falk et al, 2005 & 2007; Lyras et al, 2008 and Tocheri et al, 2007) .
The studies mainly focussed on the cranial and post-cranial metrics of LB1 in comparison to microcephalic humans, pygmies, early human species (Homo erectus, H. ergaster, H. habilis, etc) and australopithecines (A. garhi, A. africanus, P. bosei, etc.). The general conclusion was that H. floresiensis showed a better fit with the various extinct hominins than it did with the microcephalic or normal modern humans, though the studies differed as to its likely phylogeny, with affinities to Homo erectus, Homo habilis and even the later australopithecines all being proposed. LB1’s long low cranial vault is not a feature shared with modern humans, microcephalic or not (Lyras et al, 2008); LB1’s wrist morphology, based on three wrist bones, predates that of modern humans (Tocheri et al, 2007). Other pathological explanations such as Laron syndrome and cretinism were also rejected (Lyras et al, 2008).
Falk et al (2005) noted expansions in the frontal polar region of LB1. This part of the prefrontal cortex in humans and apes consists of Brodmann’s area 10 (BA10), which in humans may be involved in higher cognitive processes such as the undertaking of initiatives and the planning of future activities. The Falk study concluded that LB1’s brain could not have been a miniaturized version of Homo sapiens or H. erectus.
Citing this study, Argue et al (2006) suggested the implication is that LB1 possessed developed cognitive abilities and was able to plan, respond to conditions, use memories, and transfer information between group members.
Brumm et al (2006) considered 880,000 year old artefacts recovered from the Mata Menge site at the Soa Basin, central Flores in comparison to the Liang Bua artefacts and suggested the two show technological continuity. They suggest the hominins responsible for the Liang Bua artefacts were also responsible for those at Mata Menge, though no hominin remains have been recovered from the latter site.
What are we to make of all this? The case for Homo floresiensis being a pathological modern human does not strike me as being very convincing and on the balance of probabilities I would cautiously accept that it is indeed a new species of hominin. Obviously further evidence, in particular evidence that can be tied to the earlier tool finds, would be highly desirable.
Could H. floresiensis be an intermediate between early Homo and late Australopithecus that migrated out of Africa prior to 2 million years ago (Argue et al, 2006)? It’s not impossible that enhanced cognitive function evolved more than once, in Homo habilis and its descendants and in Homo floresiensis (though the latter would have to be transferred to a new genus to avoid paraphyly should this hypothesis become accepted). Nor would it be impossible for such a hominin to diffuse from Africa, given that the ancestors of the orang-utans did millions of years earlier. The main problem is there is absolutely no other evidence supporting dispersal from Africa of any australopithecine species or of Homo habilis, or of anything intermediate between the two. Homo georgicus, the small-brained hominin from Dmanisi, Georgia, has been touted as evidence Homo habilis did migrate from Africa, but it has now been shown to have a derived Homo ergaster (African Homo erectus) body plan.
Early Homo erectus, or something of that grade seems a more plausible ancestor. The tool technology is consistent with that of the first H. erectus dispersal from Africa, which seems to have happened before the invention of the later Mode II Acheulian hand-axe tradition. The cognitive abilities of Homo floresiensis were probably commensurate with such technology, which predates the emergence of modern human behaviour. As such, therefore, H. floresiensis would have lacked the complex language of modern humans, though it probably had language of sorts.
The question of how the forbears of these people reached Flores in the first place has led some to speculate that they must had the ability to build boats, since Flores – unlike many islands in the Indonesian archipelago – was never connected to the mainland, even during the maximum extent of the ices ages, when sea-levels dropped. But they could have been swept out to sea and stranded there by a natural occurrence such as a flash-flood or a tsunami, possibly on a raft of matted vegetation. This is believed to have been the way the ancestors of the New World monkeys reached South America from Africa; nobody is suggesting that they built boats!
Probably the most controversial idea is that Homo floresiensis survived into modern times and is the mythological Ebu Gogo said to have been living on Flores when the Portuguese arrived 400 years ago, and some claim were still being seen as recently as 100 years ago; and that similar people are the basis of similar legends such as the Orang Pendek from Sumatra and even leprechauns in Ireland?
I will admit to being sceptical (decidedly so about leprechauns!), if only because “little people” are so prevalent in world folk traditions that if these were due to actual diminutive hominins, concrete evidence would have emerged by now. However if an endemic dwarf hominin species can arise on Flores, there is certainly no reason to suppose similar species could not arise elsewhere and it is quite possible that evidence from similar genetically-isolated locations might come to light in the future.
References:
Debbie Argue, Denise Donlon, Colin Groves, Richard Wright (2006): Homo floresiensis: Microcephalic, pygmoid, Australopithecus, or Homo? Journal of Human Evolution 51 (2006) 360-374.
P. Brown, T. Sutikna, M. J. Morwood, R. P. Soejono, Jatmiko, E. Wayhu Saptomo & Rokus Awe Due (2004): A new small-bodied hominin from the
Late Pleistocene of Flores, Indonesia, Nature Vol. 431 28 October 2004.
Adam Brumm, Fachroel Aziz, Gert D. van den Bergh, Michael J. Morwood, Mark W. Moore, Iwan Kurniawan, Douglas R. Hobbs & Richard Fullagar (2006): Early stone technology on Flores and its implications for Homo floresiensis, Nature Vol. 441 1 June 2006.
Dean Falk, Charles Hildebolt, Kirk Smith, M. J. Morwood, Thomas Sutikna, Peter Brown, Jatmiko, E. Wayhu Saptomo, Barry Brunsden, Fred Prior (2005): The Brain of LB1, Homo floresiensis, Science Vol. 308 8 April 2005.
Dean Falk, Charles Hildebolt, Kirk Smith, M. J. Morwood, Thomas Sutikna, Jatmiko, E. Wayhu Saptomo, Herwig Imhof, Horst Seidler and Fred Prior (2007): Brain shape in human microcephalics and Homo floresiensis, PNAS February 13, 2007 vol. 104 no. 7 2513–2518.
T. Jacob, E. Indriati, R. P. Soejono, K. Hsu, D. W. Frayer, R. B. Eckhardt, A. J. Kuperavage, A. Thorne and M. Henneberg (2006): Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities, PNAS September 5, 2006 vol. 103 no. 36 13421–13426.
G.A. Lyras, M.D. Dermitzakis, A.A.E. Van der Geer, S.B. Van der Geer, J. De Vos (2008): The origin of Homo floresiensis and its relation to evolutionary
processes under isolation, Anthropological Science, 1 August 2008.
R. D. Martin, A. M. MacLarnon, J. L. Phillips, L. Dussubieux,
P. R. Williams, W. B. Dobyns (2006): Comment on ‘‘The Brain of LB1,
Homo floresiensis’’, Science 19 May 2006 Vol. 312.
M. J. Morwood, P. Brown, Jatmiko, T. Sutikna, E. Wahyu Saptomo, K. E. Westaway, Rokus Awe Due, R. G. Roberts, T. Maeda, S. Wasisto & T. Djubiantono (2005): Further evidence for small-bodied hominins from
the Late Pleistocene of Flores, Indonesia, Nature Vol. 437 13 October 2005.
Scarre C (2005) (Ed): “The human past”, Thames & Hudson.
Matthew W. Tocheri, Caley M. Orr, Susan G. Larson, Thomas Sutikna,
Jatmiko, E. Wahyu Saptomo, Rokus Awe Due, Tony Djubiantono,
Michael J. Morwood, William L. Jungers (2007): The Primitive Wrist of Homo floresiensis and Its Implications for Hominin Evolution, Science Vol. 317 21 September 2007.
© Christopher Seddon 2009
Monday, 5 January 2009
West Kennet Long Barrow
West Kennet Long Barrow is part of the Avebury complex of Neolithic monuments and is located on a chalk ridge 1 ½ miles south of the village (map reference SU105677).
It comprises a trapezoidal mound, 330ft (100m) long, which has a core of sarsen boulders topped out with chalk rubble from two ditches running parallel to the mound. At the eastern end of the mound are two facing pairs of burial chambers opening off from a central passage, which is terminated by a fifth chamber. At the entrance there is a 65ft (20m) semi-circular forecourt with a facade of large sarsen stones. Probably this area was used for ceremonies.
The monument was constructed around 3650 BC and is one of the largest barrows in Britain. It has been estimated that 15,700 man-hours went into its construction. Excavations carried out in 1859 and 1955-56 revealed the burials of 46 individuals of various ages. The barrow remained in use for around 1000 years, after which it was sealed up with massive flat sarcens being placed to block the entrance. The burial chambers were filled with chalk rubble.
Reference:
Pryor, F (2003): Britain BC, HarperCollinsPublishers, London.
© Christopher Seddon 2009
It comprises a trapezoidal mound, 330ft (100m) long, which has a core of sarsen boulders topped out with chalk rubble from two ditches running parallel to the mound. At the eastern end of the mound are two facing pairs of burial chambers opening off from a central passage, which is terminated by a fifth chamber. At the entrance there is a 65ft (20m) semi-circular forecourt with a facade of large sarsen stones. Probably this area was used for ceremonies.
The monument was constructed around 3650 BC and is one of the largest barrows in Britain. It has been estimated that 15,700 man-hours went into its construction. Excavations carried out in 1859 and 1955-56 revealed the burials of 46 individuals of various ages. The barrow remained in use for around 1000 years, after which it was sealed up with massive flat sarcens being placed to block the entrance. The burial chambers were filled with chalk rubble.
Reference:
Pryor, F (2003): Britain BC, HarperCollinsPublishers, London.
© Christopher Seddon 2009
Sunday, 4 January 2009
Silbury Hill
Silbury Hill is a conical, flat-topped Neolithic mound located a short distance from Beckhampton, Wilts (map reference SU100685). It is the largest man-made prehistoric mound in Europe and is 130ft (40m) high and 550ft (167m) in diameter, covering 5 acres (2.2 hectares).
Located in a region rich with Neolithic monuments, it is believed to be 4750 years old. Its purpose is unknown.
It is composed principally of chalk excavated locally. Some 8.75 million cubic feet (248,000 cubic metres) of material went into its construction. It has been calculated that it took 18 million man-hours to construct; the equivalent of 500 men working for 15 years. This suggests social complexity had evolved beyond the tribal level as only a powerful ruling elite could have mustered the resources for such a project.
© Christopher Seddon 2009
Wayland's Smithy
Wayland’s Smithy is a Neolithic burial chamber located near the village of Ashbury, Oxfordshire (map reference SU281854). It lies in a plantation of trees on the Ridgeway, not far from the Uffington White Horse and Uffington Castle.
It is named for Wayland (aka Weland, Volund or Volundr), the Saxon god of metalworking, who features in Old English and Norse mythology. Legend has it that a horse requiring a shoe may be left unattended at the site for a short while with a silver coin for payment. On return, the horse will be shod and the coin gone.
The monument does of course predate Saxon times. It was constructed in two phases: a timber chambered oval barrow built around 3700 BC and a trapezoidal stone chambered long barrow built around 3400 BC. The site is thus of particular interest as it illustrates the transition from timber chambered barrows to stone chamber barrows.
The remains of 14 bodies from the first period of construction were located during excavations in the 1960s. Previously, in 1919, the remains of seven adults and one child from the second phase were discovered.
© Christopher Seddon 2009
It is named for Wayland (aka Weland, Volund or Volundr), the Saxon god of metalworking, who features in Old English and Norse mythology. Legend has it that a horse requiring a shoe may be left unattended at the site for a short while with a silver coin for payment. On return, the horse will be shod and the coin gone.
The monument does of course predate Saxon times. It was constructed in two phases: a timber chambered oval barrow built around 3700 BC and a trapezoidal stone chambered long barrow built around 3400 BC. The site is thus of particular interest as it illustrates the transition from timber chambered barrows to stone chamber barrows.
The remains of 14 bodies from the first period of construction were located during excavations in the 1960s. Previously, in 1919, the remains of seven adults and one child from the second phase were discovered.
© Christopher Seddon 2009
Friday, 2 January 2009
Homo habilis
Introduction:
Homo habilis ("handy man") is an early human species that lived between 2.33 to 1.44 million years ago and is quite possibly the earliest member of genus Homo, though acceptance of it being an ancestor to modern humans or indeed of it being a human species at all is not universal. The species was first described by Louis Leakey in 1964.
Fossil Record:
Homo habilis is known from fossils recovered from Olduvai Gorge, Tanzania; East Turkana, Kenya; Sterkfontein, South Africa; and Hadar in the Awash Valley of Afar Depression, Ethiopia.
The first specimen to be discovered, now known as OH7, comprising a partial cranium and mandible, was discovered by Jonathon and Mary Leakey at Olduvai Gorge on 4 November 1960 and has been dated to 1.75 million years old. Other findings from Olduvai Gorge include OH 24, a cranium discovered by Peter Nzube in 1968 and believed to be 1.8 million years old; OH 13 (partial cranium, mandible and maxilla, discovered by N. Mbuika in 1963, 1.66 million years old); OH 8 (foot, probably from the same individual as OH 7, discovered 1960) and OH 62 (partial skeleton, including upper and lower limbs, believed to be female, discovered by Donald Johanson and Tim White in 1986, 2.0 million years old).
KNM-ER 1805 and KNM-ER 1813 were both discovered at Koobi Fora, East Turkana. KNM-ER 1805 is a partial cranium, maxilla, and mandible, dated to 1.74 million years old. The finder and the date of discovery are unknown. KNM-ER 1813 is a cranium dated to 1.8 million years old discovered by K. Kimeu in 1973.
KNM-ER 42703, also from Koobi Fora, is a right maxilla with an estimated geological age of 1.44 million years. It was discovered by John E. Kaatho in 2000. This is the youngest specimen assigned to Homo erectus, and is notable for being younger than KNM-ER 42700: a small, well preserved calvaria with an estimated geological age of 1.55 million years that has been assigned to (African) Homo erectus.
The Sterkfontein specimens include the partial cranium STW-53 discovered by A.R. Hughes in 1976 and dated 1.5 – 2.0 million years old.
From Hadar comes the maxilla AL-666-1, discovered by William Kimball and dated to 2.33 million years old, the oldest specimen with affinities to Homo habilis.
Description:
Homo habilis had a cranial capacity of between 509-675cc (Cameron & Groves, 2004), considerably larger than its putative ancestors, the australopithecines (375-500cc); and that of present-day chimpanzees (400cc), but much less than that of modern humans. It had a prognathic face (jutting jaw), moderate brow-ridges; no saggital keeling (a raised area along the centre of the skullcap); reduced dentition relative to australopithecines; and proportionately long arms and short legs relative to modern humans. It had an ape-like conical ribcage and possibly retained the ape-like ability of arboreal locomotion.
There was a degree of sexual dimorphism in the species. OH 62 which, as noted above, is believed to have been female, was about 1m tall and probably weighed 30kg. Males were probably around 1.3m tall and weighed around 36kg.
Technology:
Homo habilis is generally associated with the Oldowan industry (or Mode I), named for Olduvai Gorge by Louis and Mary Leakey because they were first recognised there. The Oldowan is the earliest stone tool industry and examples dating to around 2.5 million years old are known from Gona, Bouri and Hadar in Ethiopia; from Lokalelei, West Turkana, Kenya dating to 2.4 million years old; from Koobi Fora dating to 1.9 million years old and from Olduvai Gorge dating to 1.8 million years old.
The Oldowan is associated with a number of hominin species and is therefore a toll-making tradition rather than a particular culture. In addition to Homo habilis, the tradition may be associated with Parantropus (“robust australopithecines”) and the “late” gracile species Australopithecus garhi. The latter, discovered in 1997, was found in association with large animal bones showing cut-marks from stone tools. Although no actual tools were directly associated with the fossils, it seems likely that A. garhi made and used stone tools. The remains have been dated to 2.5 million years old. In addition, the Oldowan survived Homo habilis and is associated with a number of later human species.
The Oldowan is characterised by very simple stone tools. The main types are choppers made from cobbles or angular blocks of stone; hammer-stones, which are unmodified chunks that show signs of having been used as hammers in tool manufacture; scrapers made from both cores and retouched flakes detached from cores. Although there is a considerable variety and other types such as discoids and polyhedrons are recognised, much of the variation can be explained in terms of differences in the nature of the raw material available. The overall strategy was likely a least-effort strategy to produce either flakes with sharp cutting edges or cores for chopping. It seems unlikely that the Oldowan toolmakers mastered the sophisticated stone reduction strategies seen in later tool-making traditions.
Evolutionary history of Homo habilis:
The accepted view of human evolution has become considerably more complicated over the last twenty years and it is now recognised that the traditional view of progressive evolution from australopithecine to H. habilis to H. erectus and finally to H. sapiens is at best an oversimplification.
The picture for Homo habilis was complicated in the 1980s by the discovery that fossils previously assigned to Homo habilis actually belonged to two species – Homo habilis and Homo rudolfensis, although it does now seem likely that the latter is an australopithecine-type upright ape, off the line of human evolution.
Homo habilis is believed to have evolved from an australopithecine species, but there is no consensus as to which of those currently known, if any. The traditional assumption that Homo ergaster (i.e. African Homo erectus) evolved from Homo habilis has recently been challenged by the discovery that the two species were sympatric (co-existing) in the Lake Turkana basin in Kenya for almost half a million years, implying that they must have occupied different niches and leading some to believe that the two species diverged from a common ancestor 2.3 million years ago rather than one evolving from the other.
On the other hand Homo habilis appears in the fossil record some 300,000 years before Homo ergaster. Unless earlier H. ergaster remains come to light, it seems likely that a proto-ergaster population split away from an earlier population of H. habilis and only later came into contact with a population of the ancestral species.
For now, then, it is still widely accepted that Homo habilis is ancestral to all later human species, including Homo sapiens.
References:
Cameron D & Groves C (2004): Bones, Stones and Molecules: “Out of Africa” and Human Origins, Elsevier Academic Press.
Leakey LSB, Tobias PV & Napier JR (1964): A New Species of Genus Homo from Olduvai Gorge, Nature No. 4927, 4 April 1964.
Scarre C (2005) (Ed): “The human past”, Thames & Hudson.
F. Spoor, M. G. Leakey, P. N. Gathogo, F. H. Brown, S. C. Anton, I. McDougall, C. Kiarie, F. K. Manthi & L. N. Leakey (2007): Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya, Nature Vol 448 9 August 2007.
© Christopher Seddon 2009
Homo habilis ("handy man") is an early human species that lived between 2.33 to 1.44 million years ago and is quite possibly the earliest member of genus Homo, though acceptance of it being an ancestor to modern humans or indeed of it being a human species at all is not universal. The species was first described by Louis Leakey in 1964.
Fossil Record:
Homo habilis is known from fossils recovered from Olduvai Gorge, Tanzania; East Turkana, Kenya; Sterkfontein, South Africa; and Hadar in the Awash Valley of Afar Depression, Ethiopia.
The first specimen to be discovered, now known as OH7, comprising a partial cranium and mandible, was discovered by Jonathon and Mary Leakey at Olduvai Gorge on 4 November 1960 and has been dated to 1.75 million years old. Other findings from Olduvai Gorge include OH 24, a cranium discovered by Peter Nzube in 1968 and believed to be 1.8 million years old; OH 13 (partial cranium, mandible and maxilla, discovered by N. Mbuika in 1963, 1.66 million years old); OH 8 (foot, probably from the same individual as OH 7, discovered 1960) and OH 62 (partial skeleton, including upper and lower limbs, believed to be female, discovered by Donald Johanson and Tim White in 1986, 2.0 million years old).
KNM-ER 1805 and KNM-ER 1813 were both discovered at Koobi Fora, East Turkana. KNM-ER 1805 is a partial cranium, maxilla, and mandible, dated to 1.74 million years old. The finder and the date of discovery are unknown. KNM-ER 1813 is a cranium dated to 1.8 million years old discovered by K. Kimeu in 1973.
KNM-ER 42703, also from Koobi Fora, is a right maxilla with an estimated geological age of 1.44 million years. It was discovered by John E. Kaatho in 2000. This is the youngest specimen assigned to Homo erectus, and is notable for being younger than KNM-ER 42700: a small, well preserved calvaria with an estimated geological age of 1.55 million years that has been assigned to (African) Homo erectus.
The Sterkfontein specimens include the partial cranium STW-53 discovered by A.R. Hughes in 1976 and dated 1.5 – 2.0 million years old.
From Hadar comes the maxilla AL-666-1, discovered by William Kimball and dated to 2.33 million years old, the oldest specimen with affinities to Homo habilis.
Description:
Homo habilis had a cranial capacity of between 509-675cc (Cameron & Groves, 2004), considerably larger than its putative ancestors, the australopithecines (375-500cc); and that of present-day chimpanzees (400cc), but much less than that of modern humans. It had a prognathic face (jutting jaw), moderate brow-ridges; no saggital keeling (a raised area along the centre of the skullcap); reduced dentition relative to australopithecines; and proportionately long arms and short legs relative to modern humans. It had an ape-like conical ribcage and possibly retained the ape-like ability of arboreal locomotion.
There was a degree of sexual dimorphism in the species. OH 62 which, as noted above, is believed to have been female, was about 1m tall and probably weighed 30kg. Males were probably around 1.3m tall and weighed around 36kg.
Technology:
Homo habilis is generally associated with the Oldowan industry (or Mode I), named for Olduvai Gorge by Louis and Mary Leakey because they were first recognised there. The Oldowan is the earliest stone tool industry and examples dating to around 2.5 million years old are known from Gona, Bouri and Hadar in Ethiopia; from Lokalelei, West Turkana, Kenya dating to 2.4 million years old; from Koobi Fora dating to 1.9 million years old and from Olduvai Gorge dating to 1.8 million years old.
The Oldowan is associated with a number of hominin species and is therefore a toll-making tradition rather than a particular culture. In addition to Homo habilis, the tradition may be associated with Parantropus (“robust australopithecines”) and the “late” gracile species Australopithecus garhi. The latter, discovered in 1997, was found in association with large animal bones showing cut-marks from stone tools. Although no actual tools were directly associated with the fossils, it seems likely that A. garhi made and used stone tools. The remains have been dated to 2.5 million years old. In addition, the Oldowan survived Homo habilis and is associated with a number of later human species.
The Oldowan is characterised by very simple stone tools. The main types are choppers made from cobbles or angular blocks of stone; hammer-stones, which are unmodified chunks that show signs of having been used as hammers in tool manufacture; scrapers made from both cores and retouched flakes detached from cores. Although there is a considerable variety and other types such as discoids and polyhedrons are recognised, much of the variation can be explained in terms of differences in the nature of the raw material available. The overall strategy was likely a least-effort strategy to produce either flakes with sharp cutting edges or cores for chopping. It seems unlikely that the Oldowan toolmakers mastered the sophisticated stone reduction strategies seen in later tool-making traditions.
Evolutionary history of Homo habilis:
The accepted view of human evolution has become considerably more complicated over the last twenty years and it is now recognised that the traditional view of progressive evolution from australopithecine to H. habilis to H. erectus and finally to H. sapiens is at best an oversimplification.
The picture for Homo habilis was complicated in the 1980s by the discovery that fossils previously assigned to Homo habilis actually belonged to two species – Homo habilis and Homo rudolfensis, although it does now seem likely that the latter is an australopithecine-type upright ape, off the line of human evolution.
Homo habilis is believed to have evolved from an australopithecine species, but there is no consensus as to which of those currently known, if any. The traditional assumption that Homo ergaster (i.e. African Homo erectus) evolved from Homo habilis has recently been challenged by the discovery that the two species were sympatric (co-existing) in the Lake Turkana basin in Kenya for almost half a million years, implying that they must have occupied different niches and leading some to believe that the two species diverged from a common ancestor 2.3 million years ago rather than one evolving from the other.
On the other hand Homo habilis appears in the fossil record some 300,000 years before Homo ergaster. Unless earlier H. ergaster remains come to light, it seems likely that a proto-ergaster population split away from an earlier population of H. habilis and only later came into contact with a population of the ancestral species.
For now, then, it is still widely accepted that Homo habilis is ancestral to all later human species, including Homo sapiens.
References:
Cameron D & Groves C (2004): Bones, Stones and Molecules: “Out of Africa” and Human Origins, Elsevier Academic Press.
Leakey LSB, Tobias PV & Napier JR (1964): A New Species of Genus Homo from Olduvai Gorge, Nature No. 4927, 4 April 1964.
Scarre C (2005) (Ed): “The human past”, Thames & Hudson.
F. Spoor, M. G. Leakey, P. N. Gathogo, F. H. Brown, S. C. Anton, I. McDougall, C. Kiarie, F. K. Manthi & L. N. Leakey (2007): Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya, Nature Vol 448 9 August 2007.
© Christopher Seddon 2009
Thursday, 1 January 2009
Homo rudolfensis
Homo rudolfensis is a controversial taxon proposed in 1986 by Soviet anthropologist Valery Alekseyev for the old fossil hominin skull KNM-ER 1470. The skull is believed to be 1.9 million years old and was recovered in 1972 at Koobi Fora on the eastern shore of Lake Turkana (then Lake Rudolf), Kenya. The skull had previously been assigned to Homo habilis, but Alekseyev proposed reassigning it to a new species on the basis of morphological differences, most significantly a cranial capacity which, at 750cc, was significantly larger than that of H. habilis (approx 600-680cc). It also had a flatter, broader face and broader post-canine teeth (molars and premolars), with more complex crowns and roots, and thicker enamel. Subsequently other fossils including mandibles and cranial fragments, all located at Lake Turkana, were assigned to the new species and there is a roughly 50/50 split between H. habilis and H. rudolfensis remains at this site.
Cameron & Groves (2004) reject Homo status altogether for KNM-ER 1470. By phylogenetic analyses of hominin craniofacial morphology, they demonstrated that the australopithecine-like species Kenyanthropus platyops (“flat-faced man of Kenya”), a contemporary of Australopithecus afarensis (“Lucy”), was probably ancestral to KNM-ER 1470 and suggested that Homo rudolfensis should be reclassified as Kenyanthropus rudolfensis.
Homo rudolfensis’ claims as a possible ancestor to modern humans received a further blow in 2007 when KNM-ER 1470 was reconstructed by anthropologist Timothy Bromage of the New York University. Bromage noted that the jaw had been positioned incorrectly and actually jutted out further than originally believed. He downsized the cranial capacity to 526cc, below that of Homo habilis. The reconstructed skull more closely resembles those of Australopithecus (gracile australopithecines) or Paranthropus (robust australopithecines) than those of Homo (humans).
Dr. Bromage’s conclusions are not universally accepted, but if correct they would reinforce the outcome of the Cameron & Groves study.
References:
Bromage T (2007): Craniofacial Architectural Constraints Resolve Major Quandry of Human Evolution, presentation to NYUCD, released 26 March 2007.
Cameron D & Groves C (2004): Bones, Stones and Molecules: “Out of Africa” and Human Origins, Elsevier Academic Press.
© Christopher Seddon 2009
Cameron & Groves (2004) reject Homo status altogether for KNM-ER 1470. By phylogenetic analyses of hominin craniofacial morphology, they demonstrated that the australopithecine-like species Kenyanthropus platyops (“flat-faced man of Kenya”), a contemporary of Australopithecus afarensis (“Lucy”), was probably ancestral to KNM-ER 1470 and suggested that Homo rudolfensis should be reclassified as Kenyanthropus rudolfensis.
Homo rudolfensis’ claims as a possible ancestor to modern humans received a further blow in 2007 when KNM-ER 1470 was reconstructed by anthropologist Timothy Bromage of the New York University. Bromage noted that the jaw had been positioned incorrectly and actually jutted out further than originally believed. He downsized the cranial capacity to 526cc, below that of Homo habilis. The reconstructed skull more closely resembles those of Australopithecus (gracile australopithecines) or Paranthropus (robust australopithecines) than those of Homo (humans).
Dr. Bromage’s conclusions are not universally accepted, but if correct they would reinforce the outcome of the Cameron & Groves study.
References:
Bromage T (2007): Craniofacial Architectural Constraints Resolve Major Quandry of Human Evolution, presentation to NYUCD, released 26 March 2007.
Cameron D & Groves C (2004): Bones, Stones and Molecules: “Out of Africa” and Human Origins, Elsevier Academic Press.
© Christopher Seddon 2009
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