A team of scientists working in Georgia, in the former Soviet Union, has unearthed the remains of four human-like creatures dating to 1.8 million years ago, which they say sheds new light on a key stage in human evolution. The specimens are the oldest hominids to ever be found outside of Africa.
The Dmanisi site where the bones were discovered, was once near a lava flow where these primitive humans are believed to have scavenged carcasses for meat. But it appears these early humans ancestors became the unfortunate victims of a large carnivore, as their collective bones were marked by animal teeth and found in a lair-like deposit.
In the journal Nature, the researchers outline details of the partial skeletons uncovered. The bones are a mixture of primitive and advanced features, team leader David Lordkipanidze explains. These early hominids were likely “ancient pioneers”, as they appear to be among the first to leave Africa to colonize other parts of the world.
"Dmanisi is a real gift, because nothing in the world exists like this for this time," says lead author David Lordkipanidze.
Discovered in the early 1990s, the Dmanisi site has been a rich source of remains and artefacts from the early Pleistocene Epoch. Studying the various skulls and jaws has given scientists important information about the early species that lived here. But until recently they had little information about the rest of the skeleton. The remains uncovered at the town of Dmanisi consist of the partial skeleton of an adolescent individual associated with a skull, and the "post-cranial" remains of three adults.
The well-preserved fossils resemble Homo erectus, a species from the genus Homo that first appeared in Africa some two million years ago and quickly spread throughout Europe and much of Asia.
Lordkipanidze and his colleagues note that the skeletal fossils of shoulder, arm, spine and leg show that the individuals were small (about 50 kilograms on a frame of some 150 centimetres tall), had modern-human body-limb proportions. They have remarkably human-like spines and lower limbs that would have been well suited for long distance travel. Their feet had well-developed arches. The small difference in the size of males and females would put them in the same company as Homo erectus and Homo sapiens.
However, they also have relatively small brains and primitive upper limbs, traits which they share with the earlier Homo habilis, and even with the more primitive Australopithecus, such as the famous “Lucy”, specimen which lived in Africa some four million years ago.
"The really important point is you have multiple individuals from the same time and location," notes Tim White, a palaeoanthropologist at the University of California, Berkeley. With just one individual specimen it is quite difficult to determine whether a specific feature such as head size is typical of the entire species or just characteristic of that one individual. However, finding the remains of three adults and an adolescent all in the same place, presents a much clearer picture of what the species was like as a whole.