First out of Africa?

In 1991 archaeologists working at the Georgian site of Dmanisi, which had been an important town on the Silk Road, found human remains, but they lay beneath the level at which several extinct mammals had been found.  As work progressed in the deeper levels, head bones emerged.  They were exceedingly primitive, and associated with equally archaic tools; not the elegant biface stone tools of Homo erectus and later, truly human people, but from the Oldowan culture found with the earliest Homo habilis in Tanzania.  The first estimate of their age, based on the mammal remains, was 1.6 Ma.  Apart from disputed finds in Indonesia and China, the Dmanisi hominids were the oldest found outside of Africa.  Yet at that time, the larger, more brainy H. erectus was thriving in Africa, using the Acheulean biface axes.  For the Georgian archaeologists, and the growing number of international collaborators, 9 years of painstaking work lay ahead before enough data had been gathered to draw conclusions confidently.  A well illustrated summary of what Dmanisi has revealed appeared in the November issue of Scientific American ( Wong, K. 2003.  Stranger in a new land.  Scientific American, v. 289(5), p. 54-63).  Lots fell into place, when eventually the stratigraphic position of the hominid remains was convincingly established using radiometric dating of basalts below and above it – 1.85 and 1.76 Ma respectively.  With more cranial fossils, the Georgian team led by David Lordipanidze the late Leo Gabunia were able to show just how primitive the Dmanisi hominids were.  Their brain capacity was half that of modern humans, and detailed skull features resembled the earliest known member of the human genus, H. habilis.  They were small people too, and palaeoanthropologists really cannot decide whether they were australopithecines or part of our genus.  Lordipanidze believes that they are transitional between habilines and erects.  What is most surprising is that they migrated as far as Georgia.  That would have involved either crossing the mountains of Turkey and Iran, or, had they taken the possible route out of Africa across the Straits of Bab el Mandab (possibly dry land at the time), an even more circuitous route following the coast of Arabia and perhaps up the Tigris-Euphrates rivers.  Their journey began before H. erectus invented the biface axe, which up to now has been regarded as the first sign of both a leap in intellect and the beginning of some command over the rest of nature.  The Dmanisi hominids made it and survived, despite their apparently puny frames, if the abundance of animal bones at the site marks long occupation.

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