Neanderthal face is not a result of adaptation to extreme cold: Study
By ANIMonday, January 3, 2011
WASHINGTON - The long held belief that the Neanderthal nose was a result of adaptations to extreme cold may not be all it seems, say researchers.
The finding is based on a study conducted by researchers from Roehampton University, Universitat Greifswald and The Natural History Museum, London.
Many of the morphological features of Homo neanderthalensis, including the reputed large size of its paranasal sinuses, have been interpreted as adaptations to extreme cold, as some Neanderthals lived in Europe during glacial periods.
This interpretation of sinus evolution rested on two assumptions: that increased formation of air cells or cavities in the face, were an adaptation to lower ambient temperatures, and that Neanderthals have large sinuses relative to the modern human, reports Past Horizons.
However, the researchers have conducted detailed analysis of humans, primates and rodents suggesting a very different picture.
They found the first assumption is at best suspect; with the maxillary sinus undergoing a significant reduction in volume in extreme cold, in both wild and laboratory conditions.
The second assumption - that Neanderthal sinuses are large, extensive, or even over developed has been accepted since the first specimen was described in the 19th century.
This has been interpreted as the explanation for some of the distinctive aspects of Neanderthal facial form, but has never been evaluated with respect to scaling these cavities to other hominid forms.
To test the second assumption, the researchers tested previously published measurements from two-dimensional X-rays and new three-dimensional data from computed tomography of Neanderthals and temperate-climate European Homo sapiens and then scaled the results against cranial size to determine the relative size of their sinuses.
The 2D data reveals Neanderthals sinus size is comparable in scale with that seen in temperate climate H. sapiens. The 3D analysis of CT data from a smaller sample also supported this conclusion.
These results suggest that the distinctive Neanderthal face cannot be interpreted as a direct result of increased sinus size as an adaptation to resist cold stress; and so an alternative explanation is required.
The study has been reported in the Journal of Human Evolution. (ANI)
