|The bones are said to display modern |
and Neanderthal features.
The research team has dated six bones found in the Pestera Muierii cave, Romania, to 30,000 years ago.
The finds also raise questions about the possible place of Neanderthals in modern human ancestry.
Details of the discoveries appear in the US journal Proceedings of the National Academy of Sciences.
The human bones were first identified at the Pestera Muierii (Cave of the Old Woman) cave in 1952, but have now been reassessed.
Only a handful of modern human remains older than 28,000 years old are known from Europe.
Erik Trinkaus from Washington University in St Louis and colleagues obtained radiocarbon dates directly from the fossils and analysed their anatomical form.
The results showed that the fossils were 30,000 years old and had the diagnostic features of modern humans (Homo sapiens).
But Professor Trinkaus and his colleagues argue, controversially, that the bones also display features that were characteristic of our evolutionary cousins, the Neanderthals (Homo neanderthalensis).