The discovery of a 1.8-million-year-old skull of a human ancestor buried under a medieval Georgian village offers new evidence that early man was a single species with a vast array of different looks, researchers have said.
With a tiny brain about a third the size of a modern human's, protruding brows and jutting jaws like an ape, the skull was found in the remains of a medieval hilltop city in Dmanisi, according to the study published in the journal Science.
It is one of five early human skulls - four of which have jaws - found so far at the site, about 100km from the capital, Tbilisi, along with stone tools that hint at butchery and the bones of big, saber-toothed cats.
Lead researcher David Lordkipanidze, director of the Georgian National Museum, described the group as "the richest and most complete collection of indisputable early Homo remains from any one site".
"This is important to understanding human evolution," he said.
The skulls vary so much in appearance that under other circumstances, they might have been considered different species, said co-author Christoph Zollikofer of the University of Zurich.
"Yet we know that these individuals came from the same location and the same geological time, so they could, in principle, represent a single population of a single species," he said.
For years, some scientists have said humans evolved from only one or two species, much like a tree branches out from a trunk, while others say the process was more like a bush with several offshoots that went nowhere.
The researchers have compared the variation in characteristics of the skulls and found that while their jaw, brow and skull shapes were distinct, their traits were all within the range of what could be expected among members of the same species.
Credit;Aljazeera
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