Objectives: The nasal turbinates directly influence the overall size, shape, and surface area of the nasal passages, and thus contribute to intranasal heat and moisture exchange. However, unlike the encapsulating walls of the nasal cavity, ecogeographic variation in nasal turbinate morphology among humans has not yet been established.Here we investigate variation in inferior nasal turbinate morphology in two populations from climatically extreme environments.Materials and methods: Twenty-three linear measurements of the inferior turbinate, nasal cavity walls, and airway passages were collected from CT scans of indigenous modern human crania from Equatorial Africa (n = 35) and the Arctic Circle (n = 35).MANOVA and ANCOVA were employed to test for predicted regional and sex differences in morphology between the samples.Results: Significant morphological differences were identified between the two regional samples, with no evidence of significant sexual dimorphism or region-sex interaction effect. Individuals from the Arctic Circle possessed superoinferiorly and mediolaterally larger inferior turbinates compared to Equatorial Africans. In conjunction with the surrounding nasal cavity walls, these differences in turbinate morphology produced airway dimensions that were both consistent with functional expectations and more regionally distinct than either skeletal component independently. Conclusion:This study documents the existence of ecogeographic variation in human nasal turbinate morphology reflecting climate-mediated evolutionary demands on intranasal heat and moisture exchange. Humans adapted to cold-dry environments exhibit turbinate morphologies that enhance contact between respired air and nasal mucosa to facilitate respiratory air conditioning. Conversely, humans adapted to hothumid environments exhibit turbinate morphologies that minimize air-to-mucosa contact, likely to minimize airflow resistance and/or facilitate expiratory heat-shedding. K E Y W O R D S conchae, human variation, nose, respiratory tract, thermoregulation

The majority of studies of frontal bone morphology in paleoanthropology have analyzed the frontal squama and the browridge as a single unit, mixing information from different functional elements. Taking into account that the bulging of the frontal bone is often described as a species-specific trait of Homo sapiens, in this article we analyze variation in the midsagittal profile of the genus Homo, focusing on the frontal squama alone, using landmark-based superimpositions and principal components analysis. Our results demonstrate that anatomically modern humans are definitely separated from extinct human taxa on the basis of frontal bulging. However, there is minor overlap among these groups, indicating that it is necessary to exercise caution when using this trait alone to make taxonomic inferences on individual specimens. Early modern humans do not show differences with recent modern humans, and "transitional" individuals such as Jebel Irhoud 1, Maba, and Florisbad, show modern-like frontal squama morphology. The bulging of the frontal squama in modern humans may represent a structural consequence of more general cranial changes, or it could be a response to changes in the morphology of the underlying prefrontal brain elements. A subtle difference between Neandertals and the Afro-European Middle Pleistocene Homo sample is associated with flattening at bregma in the former group, a result that merits further investigation.

The early archaeological record of Beringia is complicated by the occurrence of several lithic industries. Site assemblages, dating from 14,000 to 12,800 years ago and located from the Yana‐Indigirka Lowlands of Siberia to the upper Tanana River basin, contain artifacts characteristic of the Nenana technological complex. After 12,800 years ago, site assemblages contain artifacts diagnostic of the Denali technocomplex. To explain the variation in lithic industries, we first and foremost need well‐stratified and well‐dated sites with multiple components so we securely know their ages and depositional relationships. We present excavation results of one such site located in interior Alaska, Owl Ridge, with the goal of assessing site stratigraphy, radiocarbon chronology, and natural site formation processes. Owl Ridge was visited three times during the Pleistocene‐Holocene transition with a Nenana‐complex occupation at 13,380–12,800 years ago followed by two Denali‐complex occupations at 12,540–11,430 years ago and 11,270–11,200 years ago. Assemblage change at Owl Ridge was diachronically patterned, as at the nearby Dry Creek archaeological site, and separated by two climatic events, a brief extremely windy Younger Dryas (lasting 300–250 years) and a very brief wetter period (lasting ~160 years). Our results indicate these climate and environmental conditions played a role in settlement of eastern Beringia.

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 common meatuses (p=0.0002) given the same nasal passage breadths as sub‐Saharan Africans. These results suggest that turbinate morphology likely augments other, previously documented, aspects of nasal fossa anatomy which modulate heat and moisture exchange by increasing or decreasing contact between respired air and nasal mucosa.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.