Impact of sampling strategies and reconstruction protocols in nasal airflow simulations in fossil hominins

International audienceIn their study, de Azevedo et al. (1) employ a sample of 12 individuals from Argentina of Chinese, Japanese, and Korean origin [northeastern Asians (NEA)] as representative of cold-adapted populations. However, all previous literature on the subject shows that the craniofacial morphology of these populations does not exhibit features adapted to a cold climate (e.g., refs. 2, 3). In fact, the climate of the most populated parts of China and Japan is temperate and cannot be referred to as "cold." As stated by the authors, Arctic populations drive climate-morphology correlations in many studies (4), including their own (ref. 1, p. 4). Additionally, it is surprising that no differences in the morphology of the anterior nasal region were found between the NEA and southwestern Europeans (SWE) (figure 1 of ref. 1), despite well-established differences in craniofacial features between those groups (e.g., ref. 5). This leads to a general concern that the sample is poorly described (no sex and age distributions). More importantly, no criteria are given for choosing the two individuals who were used in the subsequent computational fluid dynamics (CFD) model (ref. 1, p. 5). Consequently, this produces the main, in our opinion, issue of this study: a lack of knowledge about the factors contributing to differences in the soft tissue airway shape of those two individuals. Indeed, the nasal mucosa is an erectile tissue; its state of congestion is affected by numerous factors (e.g., nasal cycle). Therefore, the nasal airway's shape and size can fluctuate rapidly and to a very substantial degree (e.g., ref. 6). That is the reason why the criteria for choosin