Europe's earliest known modern humans existed around 45,000 years ago in a southern Italian prehistoric cave, according to new research.
The discovery means that members of our own species have been present in Europe longer than previously thought, sharing turf with Neanderthals for at least 5,000 years.
"During this time it is very likely that some contact must have been achieved, but there is no direct evidence for it," Stefano Benazzi, a physical anthropologist at the University of Vienna, told Discovery News.
He explained that "Neanderthals must have survived until about 40,000 years ago."
Before the findings of Benazzi and his team, the first known modern humans in Europe came from Romania and dated to 40,000 years ago. Early Upper Paleolithic modern human cultures are documented in the Near East to about 45,000 years ago, which previously left a gap of 5,000 years between these Homo sapiens and the ones from Romania.
"With our findings, the gap is filled," said Benazzi, whose research was published this week in the journal Nature.
Benazzi and his colleagues analyzed two teeth unearthed in 1964 at Grotta del Cavallo, a prehistoric cave in what is now Puglia. During the 1960s, the teeth were identified as coming from Neanderthals.
Benazzi and his team, however, used the latest technology, including digital models from CT scans, to examine the teeth and compare them to others belonging to Neanderthals and our species. They found that the internal and external features of the teeth better match those of modern humans.
Strengthening the determination is yet another Nature paper by a different team. That study re-examined another fossil — in this case a jaw — once attributed to a Neanderthal.
The new analysis determined the jaw belonged to an early modern human who lived between 44,200 and 41,500 years ago in what is now close to Torquay, United Kingdom.
The teeth belonged to members of what is called the Uluzzian culture. These individuals were known for fairly sophisticated bone tools, shell beads and mineral colorants that indicate these people were interested in symbolic behavior, such as wearing jewelry and sporting tattoos.
Many papers have attributed such behavior to Neanderthals in the region, but now that's in question.
Benazzi said the new findings do not provide any evidence of how the people first came to Europe, "but it is most likely that the first settlers arrived from the east, maybe along the Danube corridor."
He added, "An inherent problem in studying Pleistocene populations (prior to the Holocene or the last 10,000 years) is that the landscape has changed dramatically and large regions of the continent are now submerged. Seafaring across the Mediterranean could be a possibility, but again we have no evidence for this at the moment."
Thomas Higham of the University of Oxford, who co-authored the other Nature paper, said the new studies tell "us a great deal about how rapidly our species dispersed across Europe during the last Ice Age."
He said the discoveries also mean "that early humans must have co-existed with Neanderthals in this part of the world, something which a number of researchers have doubted."
Gerhard Weber, deputy head of the University of Vienna's Department of Anthropology, points out the studies were "made possible through technical innovations developed in the last decade."
Weber predicts that these new techniques, associated with tooth and fossil analysis as well as radiocarbon dating, will help to resolve more questions regarding "other contentious human fossil remains."
It could be that many fossils previously thought to belong to Neanderthals actually were from early modern humans.