A new discovery of skeletal remains outlined in the journal Nature sheds light on the evolutionary stages of early hominids. Researchers uncovered four partial skeletons from the dawn of the Pleistocene Epoch at the Dmanisi site in Georgia.

The well-preserved fossils mix primitive and advanced features and belong to an adolescent individual and three adults. They are nearly two million years old and thus among the oldest hominids to be found outside Africa. They appear similar to Homo erectus (Latin: "upright man"), but also have some less advanced features more likely found in the primitive hominins called Australopithocenes or the slightly newer Homo habilis. Of the more primitive features the scientists noted the relatively small brains and less advanced upper limbs.

The remains are thought to be close of what the first hominids to leave Africa looked like. Homo erectus is a species from the genus Homo that first appeared in Africa some two million years ago, thus around the time these four beings lived, and quickly spread throughout Europe and much of Asia. However, the new discovery might shatter this theoretical model, suggesting that the first Homo might have left Africa much earlier than previously believed. Homo habilis ("able man") is an older species of the genus Homo, which lived from approximately 2.6 million to at least 1.4 million years ago at the beginning of the Pleistocene.

The Georgian remains have remarkably human-like spines and lower limbs that would have been well suited for long distance travel, as well as feet with well-developed arches. Thus they are situated somewhere in between the Homo habilis and the more evolved Homo erectus.

The team which discovered the fossils was lead by David Lord-kipanidze, of the Georgian National Museum. "Absolute hindlimb length of the Dmanisi hominins is greater than in australopiths and close to that of later Homo, including modern humans," the researchers' team wrote in Nature. "This may reflect selection for improved locomotor energy efficiency."

"My hunch is that the Dmanisi and early African H. erectus fossils represent different populations of a single, highly variable species," said Daniel E. Lieberman, a paleoanthropologist at Harvard University.