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Dmanisi Man and the Out of Africa fairytale

December 8, 2009 2 comments

On exposition in the Naturalis Museum of Leiden, Netherlands 29 november 2009 t/m 28 februari 2010: the Dmanisi Man of Georgia.
A special exposition of the original skull of the earliest humanoid ever found outside of Africa. The find of this skull in Georgia raises a lot of questions all over the world on the evolution of mankind. The high age of 1.8 million year as well as the small braincapacity and the location outside Africa don’t fit into the current theories on the migration of our forebears. For the first time the skull will leave the safe of the National Historic Museum in Tbilisi, Georgia, to be exposed to the public.

The D2700 skull from Dmanisi.


I had a quick visit to the Leiden exposition of Dmanisi Man. The information was really very basic since “the book” still has to be written. Who ever said that Dmanisi is old news? Let him send me the articles everybody agrees upon. In short, three competing theories were mentioned. No evaluation, the visitors of the exposition are required to decide for themselves.

1. Out of Africa : according to this view Dmanisi Man should somehow fit within the framework of an African exodus of early humans that was theorized to have happened between 1.5 -1 million years ago. However, since Dmanisi Man was about 1.8 million years old he doesn’t fit in this scenario. So do other fossil hominins, BTW (from the start this Out of Africa was a fairy tale).

2. Earlier Out of Africa : Human (? not proven) artefacts are known from 2.6 million years ago onward. This theory proposes that the earliest humans thus could have left Africa a lot earlier and reached Asia from 2.6 million years ago onwards. New human species developed in Asia that also reached Europe. Not a word about backmigrations (a weak point).

3. Back and Forth : At any time of history humanids or early humans left Africa, developed into more advanced species and then returned to Africa.

Obviously the third option is less compromised by Afrocentrism, but I could not find additional information: what species left Africa? Were they necessarily human? Should this explain why Homo Erectus could coexist next to Homo Habilis as a separate species for so long in Africa, while previously Homo Habilis was considered the ancestor of Homo Erectus? Does the same apply to Homo Habilis in relation to Australopithecus? Of course few can be said, since no African Homo were found between the first artefacts of 2.6 million years ago and the first unequivocal remains of Homo Habilis dated 1.8-1.6 million years ago. Maybe those artefacts were not human at all and rather belong to Australopithecus? There is no evidence, only conjecture.

About the skull: the last molars (wisdom teeth) did not develop yet, so Dmanisi was a teenager. This could explain some about the outrageous low brain capacity. Possibly this skull is the best evidence we can get to prove that the human adolescent growth spurt was already a feature of the very first Homo.
At least superficially it looks quite similar to Homo Habilis. It has a horizontal brow ridge and more protruding zygomatic facial bones in common with Asiatic samples of Homo Erectus, against the V-shaped brow ridge and weaker zygomatic facial bones among the African/European samples. Unfortunately, no dentals were preserved so nothing can be said of this sample about shoveling.

Extrapolating from the Back and Forth model, I can easily imagine Homo Habilis to be from the same stock as the inmediate ancestors of Dmanisi. However, though Asiatic Homo Erectus features are clear and documented, I think the age and intermediate characteristics of Dmanisi do not support a role of this specific human type in the backmigration of Homo Erectus. Maybe rather of Homo Ergaster?

We may even reconsider the human origin completely and remind Von Koenigswald, that located the origin of humans in India. He was already familiar to Homo Modjakertensis and postulated that our predecessors were apes like Dryopithecae, Rampithecae, Sivapithecae that all seem to have either predominantly or exclusively a northern non-African distribution. The question whether or not Australopithecus should be separated completely from the humanoid line would need another evaluation, as well as the position of Afarensis within the Australopithecus family that may be invalid. Maybe the earliest bipeds arrived in a first migration wave from the Eurasia, together with the precursors of Chimpansees and Gorillas, while Lucy (Australopithecus Afarensis) and Homo Rudolfensis/Homo Habilis were the result of subsequent migration waves from Asia?

Assumptions towards an African monopoly on human origins are not getting better, and supply an ever less self-explicatory setting for the Recent Single Origin hypothesis. Its prime assumption that early hominids elsewhere but Africa are ultimately irrelevant, offers an all too easy way out of complexity and thrives on circularity: all hominids originate in Africa, thus all observed characteristics of hominids elsewhere should be assumed to originate in Africa as well. Well, did they?

Such an important assumption should be verified with available evidence. Where is the proof that Homo Erectus of the Far East derives from Homo Habilis? Homo Modjakertensis as intermediate form does not attest a straightforward evolution at all. The Dmanisi find has characteristics in common with Homo Habilis, Australopithecus and Homo Erectus of eastern asia. We should expect Homo Habilis to have evolved to Dmanisi and to Homo Modjakertenis and subsequently to Homo Erectus. In Africa we miss these kind of intermediate forms, the change or development from Homo Habilis to Homo Erectus is thus not assumed straightforward and “treelike”, but “bushlike”. However, the set of Homo Habilis characteristics is even contrary to the assumption of being ancestral: together with Homo Modjakertensis they share the intermediate position between Australopitecus and Homo Erectus having a semicircular ear canal morphology, though they fail to show the “simian gap” what would suggest an advanced development in relation to the earliest Homo Erectus that is not supported by their age.

The controversal features of the Homo Modjakertensis catalogued as “Sangiran 4” – projecting canines and precanine diastemata – are recently confirmed, and even deemed rather ‘pongid’, ie. derived from Asiatic apes rather than African apes:

This analysis shows that the Sangiran 4 palate is not unique, and shares several of these putative pongid traits with other Javan hominid fossils as well as recently described hominid specimens from Dmanisi, Georgia. These results suggest that the evolution of the earliest Asians was more complex than has previously been appreciated. — The enigma of the Sangiran 4 palate revisited, Arthur C. Durband (2008).

However, the set of characteristic of Homo Habilis against Dmanisi and/or Homo Modjakertensis also includes some that are not transitional to all modern humans. The most notorious being the shovel-shaped teeth of 80% of mongoloid people. Like Homo Erectus, these can’t be derived unequivocally from Africa and it is hard to imagine that Asiatic food required shovel-shaped teeth already for millions of years and thus to assume parallel evolution. If this comes out this would be a bad day for Asiatic restaurants all over the world, and good news for orthodontists.

The African origin of shovel-shaped teeth among Homo is precarious to say the least, although Australopithecus was reported to have them. The two Homo Habilis mentioned by Tobias for having shovel teeth are suspect finds: the position of OH6 is contested and OH16 was found completely shattered. Hardly convincing for universal currency among all early hominids. Homo Habilis and Homo Erectus coexisted for hundreds of thousand years in Africa, so maybe some evidence became mixed up, or maybe they just mixed. And what happened next?
Trinkhaus 2007: African Middle Paleolithic Modern Humans (MPMH) have chisel teeth. Archaic humans and Neanderthal, that grossly comprise all the rest in this period, have shovel-shaped teeth. Maxillary incisor shoveling remains in the Gravettian among Early European Modern Humans. The wave of chisel teeth thus only took effect much later in Europe.
Moreover, apparently ‘African’ chisel teeth never conquered Asia! The disproportionate presence of shovel teeth in asiatic populations and the preservation of this characteristic among native americans within a European civilization is a strong argument for a genetic component above “domestication”.
A relevant African Origin question: Were the “modern” chisel teeth a new evolutionary adaptation that spread from a single source in Africa, or is the chisel shape reminiscent of Homo Habilis and indicative for a minor influence of the mainstream evolutionary line that rather pertains to Homo Erectus? Could we presume continuity? Or if Homo Habilis can now be discarted as an ancestor, and Homo Erectus was an immigrant in Africa: where and how did the shovel teeth of Homo Erectus originate?

For the record, Dmanisi Man should not have come as such a surprise. We already knew of 2 million year old tools in Pakistan and Homo Modjakertensis was already dated in the same range half a century ago. So why ‘Out of Africa’ was ever proposed at all to explain Homo Erectus? The facts show the hypothesis isn’t even overdue: it was all made up from the start.

Evidence ignored for so much time is bound to make sensation today, or tomorrow for that sake. Maybe disproportionate importance of Anglosaxon scientists and their public caused undue acceptance of an Out of Africa hypothesis? Just imagine Indonesia would have been a British colony, and some kind of Leakey would have discovered those few now forgotten Homo Modjokertensis fossils. And so much evidence would have been shoveled aside by the international scientific community if Kenia simply would have been a Dutch colony instead, and Von Konigswald an anthropologists that happened to find a few bones in Kenia, after all truly just a shadow of the contemporary finds in Indonesia. In such a world of reversed political reality Dmanisi would now have been the rightful confirmation of what daring scientists already knew for over a century.

Referenced:

  • Erik Trinkaus – European early modern humans and the fate of the Neandertals, 2007, link
  • Arthur C. Durband – The enigma of the Sangiran 4 palate revisited, 2008, link (paysite)
  • G.H.R. von Koenigswald – De eerste aapmensen in Azië, 1981, ISBN 90 70157 20 9 (Dutch)
  • M. Martinón-Torres et al. -Dental evidence on the hominin dispersals, 2007, link
  • Christian R. Nichol et al. – Variation in the convexity of the human maxillary incisor labial surface , 1982, link (paysite)

Naturalis: exposition link.

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Categories: Paleoanthropology