Prehistoric World

In 2006, archaeologists announced that they had been able to identify fossils which belonged to some of the earliest modern humans to settle in Europe.

The research team involved was able to date six bones found in the Pestera Muierii cave in Romania to 30,000 years ago. The finds also raised questions at the time about the possible place of Neanderthals in modern human ancestry.

Details of the discoveries appeared in the US journal, Proceedings of the National Academy of Sciences. The human bones were first identified in 1952 at the cave known as Pestera Muierii (the 'Cave of the Old Woman'), but had now been reassessed.

Interesting mix

Only a handful of modern human remains which were older than 28,000 years old were known from Europe by this date. 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).

However, Professor Trinkaus and his colleagues argued, controversially, that the bones also displayed features which were characteristic of our evolutionary cousins, the Neanderthals (Homo neanderthalensis).

Neanderthals appear in the European fossil record about 400,000 years ago. At their peak, these squat, physically powerful hunters dominated a wide range, spanning Britain and Iberia in the west to Israel in the south and Uzbekistan in the east. Modern humans are thought to have entered Europe about 40,000 years ago and, within 10,000 years, Neanderthals had largely disappeared from the Continent.

By 24,000 years ago, the last survivors vanished from their refuge in the Iberian peninsula.

Ice age liaisons?

While many researchers of the time were still of a mind that Neanderthals were simply driven to extinction - either by climate change or competition with the moderns or, more probably, a combination of both - a handful of scientists were following the increasingly popular theory that they interbred with the incomers and contributed to the modern human gene pool.

Professor Trinkaus and his co-researchers pointed to several anatomical features of the Romanian bones which were either primitive-looking or characteristic of Neanderthals. These include a large 'occipital bun', a bump or bulge at the back of the skull, as well as other features of the lower jaw and shoulder blade.

According to Professor Trinkaus, the details which had been noted reinforced the mosaic nature of these early modern Europeans and the complex dynamics of human reproductive patterns when modern humans dispersed westwards across Europe. A strictly-held view of a population replacement of the Neanderthals was no longer tenable.

Rugged looks

Dr Katerina Harvati, a palaeoanthropologist from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, noted that the finds would further the understanding of early moderns in Europe.

She added that some traits in the fossils were either 'archaic', which meant that they were characteristic of the ancestors both of modern humans and Neanderthals, or that their evolution, presence, and absence in modern humans was poorly understood. Both the author's description and the few photographs provided in the article showed a multitude of derived modern human traits and an overwhelmingly modern morphology of the described remains.

Professor Clive Gamble, from Royal Holloway in London, UK, said the discoveries would yield valuable information about early modern humans in Europe; but he was cautious about the evidence for interbreeding with Neanderthals. It had been known for some time that the earliest modern humans in Europe were an odd-looking bunch. They were distinctive in their appearance, very heavily built, particularly in the skulls.

The question was whether these robust features showed that they were up to no good with Neanderthal women on the tundra, or whether they were just a very rugged population. The only way to tell for certain would be to look at their ancient DNA. When DNA was extracted from the classic Neanderthal skeleton, the last ancestor between modern humans and Neanderthals turned out to have lived 600,000 years ago.

Similar claims have also surrounded early human skulls from Mladec in the Czech Republic and the skeleton of a male child unearthed in 1998 at the Abrigo do Lagar Velho rock shelter in Portugal. The Lagar Velho boy, who died about 25,000 years ago, has been described as a 'hybrid', with a mixture of modern and Neanderthal features.

Principal sites showing the most recent evidence of Neanderthals - notice how the later populations are all congregated in Iberia

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