AN EARLY UPPER PLEISTOCENE AND AFRICAN ORIGIN FOR THE NEANDERTHALS

  • Patrick Fleming
  • Dublin
  • 1. February 1992

    Summary

    This contribution to the ongoing Neanderthal debate (Graves, 1991) postulates that the species Homo sapiens originated in Africa in the early Upper Pleistocene. This population then split into two groups. One group migrated to the Near East and Europe where it developed into Neanderthal. The other group stayed in Africa and developed into anatomically modern Homo sapiens. This latter group then migrated from Africa sometime later. The article will indicate that:

  • i) Homo erectus was a world-wide taxon that died out in all locations except Africa where it developed into archaic Homo sapiens (AHS);
  • ii) All archaic Homo sapiens populations (Africa, Europe, Asia) belong to the one taxon that originated in Africa;
  • iii) Anatomically modern Homo sapiens (AMH) belonged to the same species as AHS and was an adaptation to the warm conditions of Africa;
  • iv) Neanderthal belonged to the same species as archaic Homo sapiens and was an adaptation to the icy conditions of Europe and Northern latitudes.
  • THE STATUS OF HOMO ERECTUS

    Rightmire (1990) discusses the following questions in relation to Homo erectus:

  • i) whether Homo erectus is best defined as an arbitrary grade in the Homo lineage or a discrete entity;
  • ii) the necessity, or even utility, of recognizing characters which are unique (autapomorphic) to Homo erectus if this species is to be diagnosed adequately relative to other taxa;
  • iii) Evolutionary tempos and whether gradual change can be documented within Homo erectus over a long span of Pleistocene time.
  • He presents a case for viewing Homo erectus as a real taxon. His description of this species lists many characters which are primitive and which are not shared with modern humans. It is also possible to identify some traits which are clearly derived for Homo erectus in comparison to earlier Homo or Australopithecus. These include a heavy brow, midline keeling and parietal tori, strong flexion of the occiput and development of a prominent transverse torus, features of the cranial base and expansion of cranial capacity. Such characters serve to diagnose the species in a more precise way, and it can be argued, he states, that Homo erectus is not simply an arbitrarily defined segment of a lineage. This paleospecies had ancestors and probably left descendants, but these groups can be distinguished from one another on the basis of morphological comparisons. Regarding ancestors he states that two taxa may be present, as both large and small-brained morphs are present.

    Following the emergence of Homo erectus, he continues, systematic change is not easily documented. There is a trend towards endocranial expansion, which is apparent particularly in the later assemblages at Zhoukoudian and Ngandong. The growth of brain size with time depends on the date assigned to the Ngandong crania. If these crania are included then brain volume increases at a rate of about 180 ml/my. However, there is much doubt about the age of the Ngandong hominids, and assigning them a late Middle Pleistocene date biases the analysis. If a regression line is constructed without reference to Ngandong the slope drops to about 120 ml/my. This result cannot be distinguished from zero, and there is no evidence that the trend is statistically significant. Other characters change slowly or not at all. Towards the close of the Middle Pleistocene, there are signs that some of these traits begin to change more rapidly. It is during this period that populations of Homo erectus must have given way to the first representatives of a new species.

    Rightmire states that early in the Middle Pleistocene, Homo erectus can be documented from fossils found in the South, Eastern and Northwestern parts of Africa, in the Far Eastern tropics and in the cooler reaches of Northern China. Populations inhabiting these far-flung regions of the Old World are anatomically similar, and the morphology of the species seems to have changed little over more than a million years. However, differences in behaviour are apparent. In Africa, Middle Pleistocene humans utilized an Acheulian technology, while at Zhoukoudian the chopping tools associated with Homo erectus do not include hand axes. In Java, few stone tools of any sort are found in the deposits yielding ancient hominids. This suggests that Homo erectus groups were adapting differently to local circumstances.

    THE TRANSITION TO MORE MODERN FORMS

    Rightmire states that late in the Middle Pleistocene a new form of Homo evolved. These hominids, which differ significantly from Homo erectus, are known from Europe, where some of the more spectacular discoveries have come from Petralona and Arago. Other localities such as Mauer, Bilzingsleben and Vertsesszöllös are less complete and consequently less informative, but are likely to be equally ancient. Dates are very approximate for all these European specimens. Even the oldest (Mauer?) may be less than 450,000 B.P. Crania which display an advanced morphology have turned up also in Africa at Bodo (Ethiopia), Lake Ndutu (near Olduvai Groge), Broken Hill (now Kabwe) and Elandfontein. In China important discoveries have been made at Dali and other sites. As in Europe dating is very imprecise, although it can be established that the fossils cover a substantial span of the Middle Pleistocene. Workers such as Weidenreich, Coon and Wolpoff argue that this change was continuous in different geographical regions. They assume that the change was gradual and that populations of late Homo erectus were succeeded by local populations of Homo sapiens in an unbroken progression. Few if any groups became extinct. The distinction between the two groups is seen as arbitrary or is simply ignored.

    Rightmire himself adopts an opposing view. Homo erectus was a stable taxon, distinct in important ways from all later Pleistocene humans. It was pushed towards extinction and actually replaced by members of an anatomically advanced species. In some, probably many, regions such extinction was complete, and there was no local continuity. If this version of events is more or less correct then one would expect to see more abrupt changes in the record. Traits characteristic of Homo erectus would not always be carried into later populations of the same geographical area, where, instead, new trends in morphology should be established. Such novel features would be shared by all members of the descendant species, who would have dispersed widely following a later Middle Pleistocene origin. Rightmire presents evidence that the hominids from Lake Ndutu, Broken Hill, Petralona and Arago Cave differ in their morphology from Homo erectus. He refers to them as Homo sapiens although it is obvious that they display a number of archaic characteristics. In fact there is, he states, doubt about how the Broken Hill or the Arago people should be sorted and how these populations should be named. A number of authorities argue that the European specimens are Homo erectus, while other suggest that a name like Homo Heidelbergensis may be more appropriate.

    In his comparison of the African specimens Rightmire states that they should all be grouped together on grounds of broadly similar morphology. The small size and relatively low cranial capacity estimated for Ndutu may indicate that this individual is female, whereas the larger specimen from Broken Hill is likely to be male. Characters of the occipital, mastoid and tympanic parts of the cranium, which are quite well preserved, seem to set these hominids apart from Homo erectus. In discussing the European fossils and comparing them to the African, Rightmire states that Petralona and Arago 21 are two of the best crania from the European Middle Pleistocene. Brows are large especially in Petralona where the torus is almost as thickened as in Broken Hill. In the Arago, Petralona and African faces the glabella is strongly projecting. Neither Petralona nor Arago exhibits any midline keeling. Petralona resembles the Broken Hill specimen in measurement of facial projection except at subspinale, which is slightly further forward relative to an axis through the auditory openings.

    If these fossils are not Homo erectus, continues Rightmire, then it must next be agreed, whether multiple lineages of more modern Homo are to be recognized in the later Middle Pleistocene. Here very different views have been expressed. Wolpoff would include all of the hominids of Europe in a single highly dimorphic group. To him it is unimportant whether the root of this lineage is termed Homo erectus or Homo sapiens. All of its members are said to be connected in an unbroken evolutionary stream, both with the Neanderthals and with modern humans. Stringer (1983, 1985) has emphasized differences between later Middle Pleistocene hominids such as Swanscombe and Biache which clearly share apomorphic (derived) characters with the Neanderthals, and a more archaic assemblage including Arago and Petralona. These latter show few if any of the specialized traits associated with the Neanderthals of Europe and the Middle East. Instead they may be lumped broadly with archaic humans from other geographic regions, including sub-Saharan Africa. Stringer et al (1979) have suggested that fossils such as Petralona, Arago, Mauer, Broken Hill and Bodo may represent a primitive grade of our own species. Tattersall (1986) argues that taxic diversity within Homo has been seriously underestimated. He notes that legitimate species must be identified and described before the phylogeny of hominids can be investigated.

    Rightmire states that on the basis of his own observations and measurements it is reasonable to assign Ndutu, Broken Hill, Petralona and the Arago remains to a single taxon distinct from Homo erectus and later Neanderthals, even if the Arago specimens display a few Neanderthal characters. There is no justification, he states, for separating the African and European assemblages. However, he endorses Tattersall's point that groups exhibiting the archaic morphology of Broken Hill or Petralona should be set apart from anatomically modern people. To lump all recent humans, Neanderthals, and an assortment of Middle Pleistocene fossils together in one taxon is to ignore important differences. If it is accepted that archaic Homo sapiens in Africa, Europe and Asia belongs to one taxon it must be determined where the taxon originated.

  • a) Klein (1989) argues that Homo erectus died out in Asia and left no descendants. Stringer et all (1988) state that late Middle to Late Pleistocene fossils from China (e.g. Yinkou and Dali) show a change from the (local) Middle Pleistocene pattern, through a greater resemblance to Europe and Middle Pleistocene hominids (e.g. Swanscombe, Broken Hill). This would indicate to the present writer an immigrant population from, possibly, Africa.
  • b) A European source for archaic Homo sapiens is problematic. Very few, if any, fossils of an ancestor i.e. Homo erectus, have ever been found in Europe if one assigns Petralona, Arago etc. to archaic Homo sapiens itself. Therefore there was no source population. That only leaves an African origin.
  • THE ORIGIN OF ANATOMICALLY MODERN HUMANS

    Anatomically modern humans must have evolved from archaic Homo sapiens. There is no other fossil candidate. Since archaic Homo sapiens fossils have been found in Africa, Europe and Asia, the AMH could have originated in one or more of these locations. Cavalli-Sforza et al (1988) have indicated that AMH diffused from Africa about 90,000 B.P. Fossils from African sites such as Border Cave and Klassies River Mouth Cave support this. The dating of the Border Cave finds are problematic, but the Klassies River site indicate that AMH flourished in Southern Africa about 100,000 B.P. As far as recent human evolution is concerned this article has indicated:

  • i) AHS world-wide was one taxon;
  • ii) AMH developed from this AHS population in Africa.
  • Now it must be established that:
  • iii) Neanderthal developed from this AHS population;
  • iv) AHS, Neanderthal and AMH are the one species, Homo sapiens.
  • There is general consensus among specialists that Neanderthal developed slowly, in Europe, from the Arago/Petralona/Swanscombe group. The reasoning is that Neanderthal must have developed from the previous hominid in that area. But on morphological grounds Neanderthal could have developed from any AHS population in Europe, the Near East or Africa. The central question concerning Neanderthal is whether they were a separate branch from Homo sapiens that ended in extinction or, were they closely related to Homo sapiens? Neanderthal must have emerged from one of two stocks:
  • i) European AHS;
  • ii) African AHS
  • .An origin in Asian AHS is unlikely. If Rightmire is correct in saying that the African and European AHS are one species it would not seem to matter which AHS group Neanderthal emerged from. Further, it is accepted by many that AMH developed from African AHS. This would intimately bind AHS, Neanderthal and AMH, possibly in one species. However, there is another scenario. It has been argued by Stoneking et al (1989) that Homo sapiens originated in Africa about 200,000 B.P. (using the 3% mutation rate). This has recently been confirmed by Vigilant et al (1991) in a paper which avoided the confusion over certain conceptual issues in the Stoneking (1989) paper.

    From fossil evidence this would make the common ancestor a member of an anatomically archaic group. Rightmire may very well be correct in saying that European and African AHS were one species, but this can only have been true up to about 200,000 when a new species emerged. It is possible to refer to a new species because of its lack of interbreeding with previous hominids. This is indicated in Stoneking's paper where it is argued that if interbreeding had taken place then the mtDNA of modern humans would be five times more divergent than actually observed so far. We must therefore refer to an old AHS group and a new AHS group (called AHS I and AHS II hereafter).Now the original question about Neanderthal origins becomes, did Neanderthal emerge from:

    i) The old, pre 200,000 B.P. species (Africa, Europe) or

    ii) the new, post 200,000 B.P. species (Africa only)?If Neanderthal were a member of the old AHS species then the hominid would be distantly related to AMH but of a different species, making inter-breeding questionable.

    If Neanderthal were a member of the new AHS species, then the hominid and AMH would belong to the same species, making interbreeding possible. So, from which group did Neanderthal emerge:

  • i) African AHS I;
  • ii) European AHS I;
  • iii) African AHS II?
  • It is postulated in this article that the source was the African AHS II group. This population, sometime after its emergence, split into two groups. One group migrated to Europe and Eastern Asia, probably through the Near East where it developed into Neanderthal. The other group stayed in Africa where it developed into AMH. This latter group then split into two further groups. One group stayed in Africa and the other group spread around the globe. This model implies that the European and African AHS I groups died out. The apparent continuity to Neanderthal in Europe being taken up by the African AHS II migrants.

    CHARACTERISTIC NEANDERTHAL MORPHOLOGY

    Morphologically, the Neanderthals can be distinguished from all other people, fossil or living, primarily in the skull and face. Trinkaus (1986) and Klein (1989) has discussed the functional implications of this morphology:

    .i) the relative shortness of the forearm and lower leg may have been an adaptation to the cold climates that many Neanderthals faced;

    ii) the functional interpretation of the Neanderthal facial structure i.e. the forward placement of the jaws and the large size of the incisors may reflect the habitual use of the anterior dentition as a tool, perhaps mostly as a clamp or vice. This use could also account in whole or in part for such well known Neanderthal features as the long face, the well-developed supraorbital torus, and even the long, low shape of the cranium.

    iii) The large, Neanderthal nose, located far in front of the brain could have functioned to warm cold air before it reached the lungs. It is also possible however that the large nose served to dissipate body heat during frequent periods of heightened activity.

    THE MIGRATIONS FROM AFRICA

    The dates of the migration of African AHS II and the subsequent migration of AMH are of interest in this matter. The hypothesized early migrants would have brought their lithic technology with them. This technology is called Mousterian in Europe and the Near East, and the Middle Stone Age (MSA) in Sub-Saharan Africa. According to Deacon (1989) the MSA started in Southern Africa about 125,000 years B.P. Therefore the AHS II migration could only have occurred after that. According to Cavalli-Sforza et al (1986) anatomically modern man migrated from Africa about 92,000 years B.P. So based on this data, the initial migration of archaic man was between 125,000 B.P. and 92,000 years B.P. If the African AHS II migrated through the Middle East to Europe one would expect to find his earliest fossils in the Middle East. The earliest fossils from this area are:

  • i) Zuttiyeh;
  • ii) Tabun.
  • i) Zuttiyeh: According to Vendermeersch (1989) this represents a pre-Mousterian, Acheulian population in the Levant. It has some Neanderthal features such as a marked brow ridge. However certain other features, which are already apparent in pre-last glaciation Preneanderthals, are different from Zuttiyeh. He states that the typical morphology of the Neanderthal skull had already been established (in all its features) by the middle of the Riss glacial period. Any proposal of a phyletic link between Zuttiyeh and the Neanderthals would have to admit two independent lineages leading to Neanderthal, an unlikely possibility. He completes his analysis by suggesting that the Zuttiyeh hominid, from an AHS population, evolved into a proto-Cro-Magnon population. Trinkaus (1989) sees no uniquely derived features of either modern humans or Neanderthals in the fossil. He is quoted by Klein (1989) as being of the opinion that it is early Neanderthal. Ofer Bar-Yosef (1989) states that the fragmentary skull from Zuttiyeh is AHS dating from oxygen isotope stage 6 or 5e (145,000 - 97,000 B.P.).
  • In summary there is some evidence indicating that the Zuttiyeh fossil is archaic/early Neanderthal dating to a time compatible with a migration from Africa between 92,000 and 125,000 B.P. He either died out or developed into Neanderthal.
  • ii) Tabun: Trinkaus (1989) states that the layer E fossils preserve no uniquely derived features of either modern humans or Neanderthals. These fossils have been dated to 120,000 B.P. (Science 1991) The fossils are compatible with the postulated migration from Africa of AHS.
  • THE MOUSTERIAN/MIDDLE STONE AGE CULTURE

    A common Mousterian/Middle Stone Age covered Africa, the Near East and Europe starting about 125,000 years B.P. in Africa, a little later in the Near East and still later in Europe. This common culture included (after Klein 1989):

  • i) Stone artifacts. These are generally dominated by flakes or flake-blades, often from well-prepared cores and the principal retouched pieces are scrapers, points, and denticulates similar to those found in the contemporaneous Mousterian (Middle Palaeolithic) of Europe and the Near East. MSA assemblages resemble Mousterian ones in two further fundamental respects.
  • a) they lack formal bone, ivory or shell tools and art objects, with some rare exceptions that could represent undetected intrusions from later horizons and
  • b) they exhibit relatively little variability in time and space that cannot be attributed to differences or changes in the availability of lithic raw materials. In fact, typologically and technically, there is little to distinguish the MSA from the Mousterian, and at present the basic difference is geographic. Assemblages that would be called Mousterian in Europe, the Near East, or North Africa are called MSA in Sub-Saharan Africa.
  • ii) Non-stone artifacts. A wooden spear was found in Lehringan. Possible throwing sticks were found in Angola and Florisbad (South Africa). However deliberately shaped bone tools are unknown in Mousterian or MSA sites. Mousterian/MSA peoples left little or no evidence for art or ornament. Fragments of natural red or black pigment that Mousterian/MSA peoples brought to their sites suggest that they may have decorated perishable materials, perhaps including their own skins. They did not concentrate pigments in graves.
  • iii) Both Mousterian and MSA groups used caves and open-air sites. These sites were probably living places or camps rather than places where people killed or butchered animals. This is indicated by their very nature and by the fossil fireplaces or "hearths" that are a prominent feature in virtually every well-excavated cave where preservation conditions are appropriate.
  • iv) There are many examples of Neanderthals burying their dead. The skeletons of AMH at Skhul and Qafzeh (Israel) dated at 100,000 B.P., (Science 1991) were also found in graves. However, there is no evidence that the MSA people buried their dead, but the site sample is relatively small and the conditions for grave preservation are not as good as in Europe and the Near East. In Europe, continues Klein, the Mousterian is closely linked to the Neanderthals, and if human fossils were absent from MSA sites in Southern Africa, we might guess that the people were Neanderthals, or at least that they differed from modern people to the same extent that Neanderthals did. Clearly we would be wrong, and the well established association in the near East between Mousterian artifacts on the one hand and both Neanderthal and early moderns on the other has long shown that there is no necessary correlation between physical type and artifacts. Equally germane, it suggests that a major change in physical type may precede a major change in artifacts.
  • The present writer believes that the similarity between MSA and the European/Middle East cultures is best explained by African early Homo sapiens carrying that culture to Europe rather than a similar Mousterian culture developing independently there. The probability of two similar cultures developing independently in different areas seems rather remote. Because they belonged to the same species and shared a similar cognitive capacity and culture, the hypothesized second migration of AMH from Africa to the Near East would have allowed both groups to inter-breed. This need not necessarily have happened however. For a number of reasons they may have lived side by side without mating. This is a common occurrence as, for example, when modern Europeans met the original inhabitants of the Americas, Africa and Australia. The MSA differs from the succeeding Later Stone Age (LSA) in much the same way that the Mousterian differs from the succeeding Upper Palaeolithic.

    THE CULTURAL STATUS OF HOMO ERECTUS

    The fate of the late Homo erectus/archaic Homo sapiens population, if they did not evolve into Neanderthal, must be addressed.

    Although no Homo erectus fossils have been found in Europe, artifacts that he may have made can be identified by their contemporanity with Homo erectus elsewhere. These artifacts were part of the Acheulean tradition that was widespread both spatially and temporarily. However Binford (1989) states that the remarkable similarity in early hominid technology over vast areas calls to mind what we see in other species of animals, namely, a generic organizational basis of behaviour that is common to the species. There is nothing in the data of the Oldowan or the Acheulean to suggest in any way a "cultural" or extrasomatic mechanism of inheritance serving to make possible the occupation of varying niches by sub-populations of a single species. We are not looking at rudimentary or nascent cultural systems, instead we have a technologically aided, biologically based, panspecific form of adaptation.

    In the same paper Binford also questions the hunting prowess of Homo erectus. There were, he argues, no mass kills at Torralba, no game drives, no activity areas in which large quantities of meat were processed by socially differentiated labour units. Also, the tool suite associated with bones from lower limbs and heads, association recognized from earlier sites as a tentative indication of scavenging, is the dominant one. It seems likely that, as elsewhere, these bones were accumulated by the hominids rather than representing animals killed there. Although there is a distinctive suite of tools that covaries with carcass indicators, there is no indication that the hominids hunted or caused the death of animals. In fact, the pattern of raw material use characteristic of this suite suggests that the hominids encountered the carcasses unexpectedly and were forced to produce the tools needed to deal with them using local sources and already present lithic remains. This behaviour is consistent, Binford argues, with scavenging, and little planning depth stands behind it. James (1989) rejects the use of fire by Homo erectus at Zhoukoudian. He states that what has passed for burnt bone in the past is in fact manganese staining. Binford and Ho (1985) point out that there are no structurally defined hearths there and that the so called ash layers appear to consist of owl droppings, hyena scats and other organic accumulations that have been decalcified and burned, perhaps as a result of spontaneous combustion or surface fires.

    For these reasons, the present writer believes that serious doubt must be cast on the culture system of Homo erectus. Neither he nor AHS I show any cultural signs of an evolution to the culture possessed by the MSA sub-Saharan people and the Mousterian population of the Middle East and Europe. As already postulated the European late Homo erectus/AHS I died out as in East Asia. One population of Homo erectus had to evolve through AHS to AMH and Neanderthal. That population was in Africa.

    PRESENT PROBLEMS REGARDING THE RELATIONSHIP OF NEANDERTHAL AND ANATOMICALLY MODERN HOMO

    There are, currently, two spatial and temporal areas with an overlap of Neanderthal and AMH:

  • i) In the Middle East Neanderthal fossils found at Tabun and Kabara have been dated to 120,000 and 60,000 B.P. respectively. AMH fossils have been found at Skhul and Qafzeh, both dated to about 100,000 B.P. It therefore seems probable that both groups were contemporaries for some tens of thousands of years. It is debated whether one or two species are present. (Science 1991). Stringer et al (1991) state that the two groups used indistinguishable Middle Paleolithic technologies. Stringer et al (Nature 1991) also discuss this problem. They feel that Neanderthal and AMH were probably sufficiently closely related to allow hybridization. They make the point that mitochondrial DNA studies suggest that there is no trace of a genetic input from Neanderthal females in recent European samples. Had there been interaction then the mtDNA divergence of modern humans would be much greater than it is. This reasoning is based on Neanderthal being a very old species, descended from an older European species.
  • However, if my hypothesis is correct, interbreeding of the migrating anatomically modern Africans with the Neanderthal population of the Middle East and Europe would have been possible. Since both populations descended from the same anatomically archaic population in Africa, both would have nearly the same mtDNA divergence, as they had not been separated for more than 33,000 years at most.
  • ii) Mercier et al (1991) have dated burnt flints associated with a Neanderthal skeleton from Saint - Césaire in France to about 36,000 ± 3,000 B.P. This is one of the last known Neanderthals , and supports the proposition that the last Neanderthals coexisted with the first modern humans for several thousand years in Western Europe. This Chatelperronian technology may be based on the Aurignacian technology of the AMH. The reason for this late arrival of AMH in Western Europe is discussed by F. C. Howell (1952) who argued that the Neanderthals in Western Europe (classic Neanderthals) were isolated by the patterns of glaciation during Würm II. East-central and Eastern Europe were not particularly isolated during the Early Last glacial. There was broad continuity at least as far East as the Crimea and Southward into the Levant.
  • I postulate that the East European and Near Eastern populations (either mixed Neanderthal/anatomically modern population, or a 'pure' anatomically modern population) spread eventually into Western Europe during an interstadial. They did not mix at all or only very marginally. This lack of interbreeding could easily be explained by the higher cultural levels of the migrants, coupled with strong facial and other anatomical difference.
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