A common ecogeographic trend in the internal nasal cavity variation across Mesolithic to Bronze Age Eastern European and Caucasian populations

The ecogeographic trends in the shape of the internal nasal cavity and external facial skeleton were explored in a sample of Mesolithic, Neolithic, and Bronze Age skulls from Northeastern Europe and the Caucasus and tested against a background of the variation in recent populations from the same area. The volume, surface area, and several linear dimensions of the internal nasal cavity as well as a set of 3D landmarks of the external mid-face were collected in a sample of computed tomography (CT) scans of 121 adult male skulls from six modern human populations of Eastern Europe, Anatolia, and Caucasus (74 individuals) and seven ancient burial sites (47 individuals). Various measures of the association between nasal cavity morphology and climate revealed moderate to high levels of correlation. The modern populations from colder climates and all but one ancient group display a substantial decrease in the nasal cavity heights and widths, volume and nasal protrusion, a relative narrowing of the nasal cavity, and a substantial increment in length of the maxillary part of the cavity. These groups also exhibit a less protruding external nose, smaller orbits, and a vertically taller zygomatic region. Our results show that the suite of morphological features associated with living in a cold climate is more strongly pronounced in ancient Europeans compared with the Medieval or modern groups of the same continent.