A fragment of human lower jaw recovered from a Serbian cave is the oldest human ancestor found in this part of Europe, who probably evolved under different conditions than populations that inhabited more western parts of the continent at the same time, according to research published in PLOS ONE.

The fossil was found to be at least 397,000 years old and possibly older than 525,000 years old, a time when distinctly Neandertal traits began to appear in Europe.

The evolution of these traits was strongly influenced by periodic isolation of groups of individuals, caused by episodic formation of glaciers.

Humans in southeastern Europe were never geographically isolated from Asia and Africa by glaciers, and according to the authors, this resulted in different evolutionary forces acting on early human populations in this region.

Roksandic explains that their study confirms the importance of southeast Europe as a 'gate to the continent' and one of the three main areas where humans, plants and animals sought refuge during glaciations in prehistoric times.

She adds, "We have very few fossils of hominins in general from this time, a period that was critical for shaping the appearance and evolution of uniquely human morphology and behaviors."

Rink WJ, Mercier N, Mihailovic D, Morley MW, Thompson JW, et al. (2013) New Radiometric Ages for the BH-1 Hominin from Balanica (Serbia): Implications for Understanding the Role of the Balkans in Middle Pleistocene Human Evolution. PLoS ONE 8(2): e54608. doi:10.1371/journal.pone.0054608