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The debate that has raged about whether Neanderthals were a sub-species of modern humans may finally be over.

Researchers have identified new evidence supporting the growing belief that Neanderthals were a distinct species separate from modern humans (Homo sapiens) and deserve a more distinct identity of their own.

Experts studied the nasal complex of Neanderthals to also conclude that their extinction was probably due to competition with modern humans, and not their inability to adapt to a cooling climate.

Experts studied the nasal complex of Neanderthals (a skull dating from 50,000 BC is pictured) and say that its features evolved separately to modern humans, suggesting that Neanderthals were a distinct species separate from Homo sapiens and deserve a more distinct identity of their own

The research, led by Suny Downstate Medical Centre, in New York City, indicates that the Neanderthal nasal complex was not inferior, but simply different, to that of modern humans.

Samuel Márquez, Associate Professor at the Centre's Department of Cell Biology and his team said that previous studies into the Neanderthal nose have compared Neanderthal nasal dimensions to modern human populations such as the Inuit and modern Europeans, whose nasal complexes are adapted to cold and temperate climates.

However, the current study, published in The Anatomical Record, adds to a growing body of evidence that the upper respiratory tracts of this extinct group functioned via a different set of rules.

This is because the structures have as a separate evolutionary history and features not found among any population of humans.

Dr Márquez explained: 'The strategy was to have a comprehensive examination of the nasal region of diverse modern human population groups and then compare the data with the fossil evidence. 

The study revealed that the extinction of Neanderthals was probably due to competition with modern humans, not their inability to adapt to a cooling climate. A hunting scene is illustrated

'We used traditional morphometrics, geometric morphometric methodology based on 3D coordinate data, and CT imaging.'

Anthony Pagano, anatomy instructor at NYU Langone Medical Centre, who co-authored the study, collected 3D data from fossils in European museums.

The team looked at this data and other sets of information to 'have a feel for where these Neanderthals may lie among the human spectrum'.

William Lawson, director of the Palaeorhinology Laboratory of the Icahn School of Medicine at Mount Sinai, also in New York City, said that while the external nasal aperture (the pear-shaped opening of the skull) of Neanderthals is similar to that of some human populations, their protrusion of the midface (midfacial prognathism) is 'startlingly different'.

That difference is one of a number of Neanderthal nasal traits suggesting an evolutionary development distinct from that of modern humans.

Jeffrey Laitman, of the Icahn School of Medicine, believes that the study is a significant contribution to the question of Neanderthal cold adaptation in the nasal region, especially in its identification of a different number of features than those of cold-adapted modern humans.

His previous work has shown that there are clear differences in the vocal tract proportions of fossil humans when compared to modern humans.

He said: 'The strength of this new research lies in its taking the totality of the Neanderthal nasal complex into account, rather than looking at a single feature.

'By looking at the complete morphological pattern, we can conclude that Neanderthals are our close relatives, but they are not us.'

Ian Tattersall, of the American Museum of Natural History, who was not involved in the study commented: 'Márquez and colleagues have carried out a most provocative and intriguing investigation of a very significant complex in the Neanderthal skull that has all too frequently been overlooked.'

He hopes that future studies will demonstrate 'once and for all' that Neanderthals deserve a distinctive identify of their own.