An ancient skull may be a key piece of evidence pointing to intermingling between Neanderthals and modern humans possibly for the first time.

According to the Guardian, the researchers, whose study is published in the journal Nature, found the skull in a cave in western Galilee, northern Israel. They believed the skull belonged to a woman who lived in the region some 55,000 years ago.

"It has been suspected that modern man and Neanderthals were in the same place at the same time, but we didn't have the physical evidence. Now we do have it in the new skull fossil," Bruce Latimer, a paleontologist at the Case Western Reserve University School of Dental Medicine's Department of Orthodontics, said in a press release.

Israel Hershkovitz, the study's lead researcher from Tel Aviv University, said the skull is a significant discovery despite being only a fragment, missing its face and jaws.

"It's amazing. This is the first specimen we have that connects Africa to Europe," he told the Guardian. "We couldn't believe our eyes. We immediately realized it was a prehistoric cave and that it had been inhabited for a very long time. Because the entrance had collapsed so long ago, it had been frozen in time. Nobody had been inside for 30,000 years."

Chris Stringer, head of human origins at the Natural History Museum, told the Guardian the region in which the researchers found the skull was already believed to be a likely site for human and Neanderthal interbreeding.

"At about 55,000 years old, this is the first modern human from western Asia which is well dated to the estimated timeframe of interbreeding between early modern humans and Neanderthals," he said. "Manot might represent some of the elusive first migrants in the hypothesised out-of-Africa event about 60,000 years ago, a population whose descendants ultimately spread right across Asia, and also into Europe. Its discovery raises hopes of more complete specimens from this critical region and time period."