Archaeologists in Georgia have found a 1.8-million-year-old tooth belonging to an early species of human which they say cements the region as the home of one of the earliest prehistoric human settlements in Europe, possibly anywhere outside Africa.
The tooth was discovered near the village of Orozmani, around 100 km southwest of the Georgian capital of Tbilisi, near Dmanisi where human skulls dated to 1.8 million years old, were found in the late 1990s and early 2000s.
The Dmanisi finds were the oldest such discovery anywhere in the world outside Africa and one which changed scientists' understanding of early human evolution and migration patterns.
The latest discovery at a site 20 km away provides yet more evidence that the mountainous south Caucasus area was likely one of the first places early humans settled after migrating out of Africa, experts said.
"Orozmani, together with Dmanisi, represents the centre of the oldest distribution of old humans - or early Homo - in the world outside Africa," the National Research Centre of Archaeology and Prehistory of Georgia said, announcing the discovery of the tooth on Thursday.
Giorgi Bidzinashvili, the scientific leader of the dig team, said he considers the tooth belonged to a "cousin" of Zezva and Mzia, the names given to two near-complete 1.8-million-year-old fossilised skulls found at Dmanisi.
"The implications, not just for this site, but for Georgia and the story of humans leaving Africa 1.8 million years ago are enormous," said British archaeology student Jack Peart, who first found the tooth at Orozmani.
"It solidifies Georgia as a really important place for paleoanthropology and the human story in general," he told Reuters.
The oldest Homo fossils anywhere in the world date to around 2.8 million years ago - a partial jaw discovered in modern-day Ethiopia.
Scientists believe early humans, a hunter-gatherer species named Homo erectus, likely started migrating out of Africa around two million years ago. Ancient tools dated to around 2.1 million years have been discovered in modern-day China, but the Georgian sites are home to the oldest remains of early humans yet recovered outside Africa.