| Summary: | The occupation of human populations in climatically diverse regions is of interest to anthropologists and clinicians alike. However, the extent to which humans have adapted to increasing respiratory demands posed by varying temperatures and humidities is still under exploration. Respiratory air conditioning is an important aspect of climatic adaptation in humans, and is governed predominantly by the amount of contact between respired air and mucosa within the internal nasal cavity. An important component contributing to internal nasal cavity shape are the nasal turbinates, which are scroll‐shaped bones that project from the nasal wall. Because the nasal turbinates directly influence the size, shape, and surface area of the mucosa‐lined nasal passages, variation in turbinate morphology may substantially impact heat and moisture exchange within the nasal fossa. However, unlike the encapsulating walls of the nasal cavity, ecogeographic variation in nasal turbinate morphology has not been established. Accordingly, this study investigated variation in inferior nasal turbinate morphology, employing linear measurements of inferior turbinate length, height, and breadth, as well as nasal passage and common meatus widths. These measurements were collected from CT‐scans of crania from two climatically distinct, mixed‐sex, modern human samples: equatorial Africans (n=33) and Arctic populations (n=30). Permutation t‐tests revealed the existence of significant ecogeographic differences in inferior turbinate morphology, with the Arctic sample characterized by significantly longer (p<0.0001), taller (p=0.0005), and wider (p=0.011) inferior turbinates compared to equatorial African individuals. Further, although the Arctic sample was found to possess slightly narrower nasal passages (p=0.015), greater breadth of the inferior turbinate resulted in substantially narrower common meatus dimensions (p<0.0001). Indeed, analysis of covariance (ANCOVA) results show that Arctic individuals would possess significantly narrower ...
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