A research team has found a complete skull of an early adult hominid that could potentially challenge views of humans evolutionary lineage.

The skull, known creatively as Skull 5, is 1.8 million years old, USA Today reports. The skull is an interesting find as nothing like it has been seen before.

The skull features an outward jutting jaw and a small cranial cavity, reminiscent of other early ancestors, but some bones that were found with Skull 5 indicate that the body was similar to Homo sapiens, with shorter arms and legs. The remains also suggest there was only one early human living at the time.

"We're not against the idea that there might have been more than one species at some point about 2 million years ago," said Christoph Zollikofer, from Switzerland's Anthropological Institute and Museum, at a news conference about the find. "But we simply say ... we don't have sufficient fossil evidence."

The skull was discovered fairly well preserved in the country of Georgia, CBS News reports. "It's almost a perfectly complete skull," executive science editor for National Geographic said. "And because of that, it has a lot of information.

Skull 5 was found with a few other partial skulls that all differ in appearance. Researchers are considering them all to be of the same species, since their variations are similar to modern humans.

USA Today notes that the fossil site in Dmanisi will be interesting as researchers continue working on the site and debate their theories on how this find affects currently held beliefs in science.

image: Wikimedia Commons