First Europeans were already running like us

Overall image of the skeleton of the Dmanisi people reconstructed

Computer reconstruction of the two most complete skeletons of Dmanisi. On the left the skeleton of an adult and on the right that of a youth. © M. Ponce de León / C. Zollikofer, University of Zurich
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The hominids from the Georgian Dmanisi are the earliest representatives of our genus outside Africa. New finds now show that these first Europeans could walk and walk like modern humans. The researchers report on their findings in the current issue of the science journal "Nature".

So far, knowledge of the earliest population of Homo erectus, the Dmanisi people, was based mainly on skull and jaw finds. Parts of the rest of the skeleton had not yet been found, so little was known about the two-legged walk, the arms and hands. Last year, scientists also found bones of the trunk skeleton and limbs of four Dmanisi hominids. Thanks to individual anatomical features, these new fossils could be assigned to previously found skulls.

"For the first time, this puzzle can be used to reconstruct an overall picture of the skeleton of Plio-Pleistocene hominids, " explains Professor Christoph PE Zollikofer of the Anthropological Institute of the University of Zurich, who is part of the international research team together with Marcia S. Ponce de Léon and Tea Jashashvili.

Dmanisi hominids with a small brain

The analysis of the latest finds show that the Dmanisi were only about 150 centimeters in size. They were smaller than the African Homo erectus. The brain of the Dmanisi hominids, between 600 and 800 cubic centimeters, was surprisingly tiny, while that of modern humans measures between 1, 200 and 1, 800 cubic centimeters. Compared to her size, her brain was as small as that of the very first member of the genus Homo from Africa, definitely smaller than that of Homo erectus in Africa and Asia.

Walk and walk like modern people

One of the scientists' most astonishing findings is that the Dmanisi hominids have essentially the same body proportions as modern humans: the legs are significantly longer than the arms, and the thighs are longer than the upper arms. The spine also shows the shape of an S, and the arch is well formed. "All these features are an unmistakable sign of the resilient two-legged gait, which allows it to travel long stretches, running or running", summarizes Zollikofer. display

The shoulders and arms of the Dmanisi people, on the other hand, were subtly different in construction from ours. In modern humans, the shoulder blades lie at rest in the resting position, while at the same time the palms are turned inwards. This is ensured by a strong torsion of the humerus. Thus, the outward rotation of the shoulder joint can be compensated by an internal rotation of the elbow joint. In the Dmanisi hominids, the humerus showed no torsion; at the same time the shoulder blades were built so that they allowed more freedom of movement.

Peculiar mosaic beings

"Functionally, at the moment we can only say that the arm movements of Dmanisi hominids differ from ours, " explains Zollikofer. "They did not stop the hominids from making a variety of stone tools and breaking big game bones to get to the marrow."

From the present perspective, the Dmanisi hominids thus appear to us as peculiar mosaic beings that combine modern and ancient features in one and the same body. From the Dmanisi hominid perspective, of course, that was not the case. They were people who were well-adjusted to their environment and had a social structure and cognitive abilities that enabled the survival of old and disabled group members.

(idw - University of Zurich, 20.09.2007 - DLO)