Computer simulations show that Neanderthal facial morphology represents adaptation to cold and high energy demands, but not heavy biting

Three adaptive hypotheses have been forwarded to explain the distinctive Neanderthal face: (i) an improved ability to accommodate high anterior bite forces, (ii) more effective conditioning of cold and/or dry air and, (iii) adaptation to facilitate greater ventilatory demands. We test these hypotheses using three-dimensional models of Neanderthals, modern humans, and a close outgroup (Homo heidelbergensis), applying finite-element analysis (FEA) and computational fluid dynamics (CFD). This is the most comprehensive application of either approach applied to date and the first to include both. FEA reveals few differences between H. heidelbergensis, modern humans, and Neanderthals in their capacities to sustain high anterior tooth loadings. CFD shows that the nasal cavities of Neanderthals and especially modern humans condition air more efficiently than does that of H. heidelbergensis, suggesting that both evolved to better withstand cold and/or dry climates than less derived Homo. We further find that Neanderthals could move considerably more air through the nasal pathway than could H. heidelbergensis or modern humans, consistent with the propositions that, relative to our outgroup Homo, Neanderthal facial morphology evolved to reflect improved capacities to better condition cold, dry air, and, to move greater air volumes in response to higher energetic requirements

Neandertal noses : a descriptive and comparative analysis of the nasal morphology of the Krapina and Vindija Neandertals

Includes bibliographical references (pages [84]-91)In a recent study, Schwartz and Tattersall outlined a series of proposed autapomorphic features for the internal nasal region of Neandertals. These features include the presence of an internal nasal margin with a medial projection, the medial expansion of the nasal cavity wall into the posterior portion of the nasal cavity, and an exposed lacrimal groove. Based on the Schwartz and Tattersall study, others have further suggested that the arrangement of crests of the inferior portion of the nasal aperture is uniquely derived in Neandertals. Schwartz and Tattersall noted the presence of these features in a small sample of Neandertals from Western Europe. Excluded from their study, perhaps because of their fragmentary nature, were Neandertal specimens from the Croatian sites of Krapina and Vindija. The present study is designed as a descriptive and comparative analysis of the nasal morphology of the Krapina and Vindija Neandertals with an emphasis on the features presented by Schwartz and Tattersall. Detailed descriptions of the nasal morphology of the Krapina and Vindija specimens are provided and comparisons are made between the two collections. Where applicable, expression of the proposed autapomorphic features was observed on the Krapina and Vindija specimens. Patterns of cresting in the lower part of the nasal aperture were documented for both samples. The internal nasal morphology of an extensive modem sample from the skeletal collections at the Field Museum in Chicago was also documented and compared to the morphology of the Krapina and Vindija Neandertal samples. The results of this analysis are inconsistent with those of the Schwartz and Tattersall study. The morphology of several of the Krapina and Vindija specimens falls within the range of variation present in the modem sample. Thus, after increasing the sample to include specimens from Krapina and Vindija, the three traits proposed by Schwartz and Tattersall are rejected as Neandertal autapomorphies. The nasal cresting patterns of Krapina and Vindija differ from specimens analyzed in the Schwartz and Tattersall study as well as from each other. Therefore, the claim of an autapomorphic Neandertal cresting pattern is rejected as well.M.A. (Master of Arts

The Ontogeny of Nasal Shape: An Analysis of Sexual Dimorphism in a Longitudinal Sample

Objectives Potential integration between the nasal region and noncranial components of the respiratory system has significant implications for understanding determinants of craniofacial variation. There is increasing evidence that sexual dimorphism in body size and associated male-female differences in energetically relevant variables influence the development of the nasal region. To better understand this relationship, we examined the ontogeny of sexual dimorphism in nasal shape using a longitudinal series of lateral cephalograms. Methods We collected a series of two dimensional coordinate landmark data from n = 20 males and n = 18 females from 3.0 to 20.0+ years of age totaling n = 290 observations across nine age groups. First, we tested whether there are sex differences in the nasal shape related to ontogenetic increases in body size (i.e., sitting height). Additionally, we examined whether there are male-female differences in patterns of nonallometric variation in nasal shape. Next, we tested whether there are sex differences in the strength of integration between the nasal region and other aspects of the facial skeleton. Results Our results indicate that there are a number of similarities in patterns of morphological variation in the nasal region between males and females. However, as sitting height increases males exhibit a disproportionate increase in nasal region height that is not present in the female sample. Moreover, the male nasal region is less integrated with the surrounding facial skeleton when compared to the female sample. Conclusions These results are consistent with the hypothesis that sex differences in nasal development are associated with male-female differences in energetically relevant variables

The Ontogeny of Nasal Shape: An Analysis of Sexual Dimorphism in a Longitudinal Sample

Objectives Potential integration between the nasal region and noncranial components of the respiratory system has significant implications for understanding determinants of craniofacial variation. There is increasing evidence that sexual dimorphism in body size and associated male-female differences in energetically relevant variables influence the development of the nasal region. To better understand this relationship, we examined the ontogeny of sexual dimorphism in nasal shape using a longitudinal series of lateral cephalograms. Methods We collected a series of two dimensional coordinate landmark data from n = 20 males and n = 18 females from 3.0 to 20.0+ years of age totaling n = 290 observations across nine age groups. First, we tested whether there are sex differences in the nasal shape related to ontogenetic increases in body size (i.e., sitting height). Additionally, we examined whether there are male-female differences in patterns of nonallometric variation in nasal shape. Next, we tested whether there are sex differences in the strength of integration between the nasal region and other aspects of the facial skeleton. Results Our results indicate that there are a number of similarities in patterns of morphological variation in the nasal region between males and females. However, as sitting height increases males exhibit a disproportionate increase in nasal region height that is not present in the female sample. Moreover, the male nasal region is less integrated with the surrounding facial skeleton when compared to the female sample. Conclusions These results are consistent with the hypothesis that sex differences in nasal development are associated with male-female differences in energetically relevant variables

Ontogenetic scaling of the human nose in a longitudinal sample: Implications for genus Homo facial evolution

Researchers have hypothesized that nasal morphology, both in archaic Homo and in recent humans, is influenced by body mass and associated oxygen consumption demands required for tissue maintenance. Similarly, recent studies of the adult human nasal region have documented key differences in nasal form between males and females that are potentially linked to sexual dimorphism in body size, composition, and energetics. To better understand this potential developmental and functional dynamic, we first assessed sexual dimorphism in the nasal cavity in recent humans to determine when during ontogeny male-female differences in nasal cavity size appear. Next, we assessed whether there are significant differences in nasal/body size scaling relationships in males and females during ontogeny. Using a mixed longitudinal sample we collected cephalometric and anthropometric measurements from n = 20 males and n = 18 females from 3.0 to 20.0+ years of age totaling n = 290 observations. We found that males and females exhibit similar nasal size values early in ontogeny and that sexual dimorphism in nasal size appears during adolescence. Moreover, when scaled to body size, males exhibit greater positive allometry in nasal size compared to females. This differs from patterns of sexual dimorphism in overall facial size, which are already present in our earliest age groups. Sexually dimorphic differences in nasal development and scaling mirror patterns of ontogenetic variation in variables associated with oxygen consumption and tissue maintenance. This underscores the importance of considering broader systemic factors in craniofacial development and may have important implications for the study of patters craniofacial evolution in the genus Homo. Copyright © 2013 Wiley Periodicals, Inc

Ontogenetic Scaling of the Human Nose in a Longitudinal Sample: Implications for Genus Homo Facial Evolution

Researchers have hypothesized that nasal morphology, both in archaic Homo and in recent humans, is influenced by body mass and associated oxygen consumption demands required for tissue maintenance. Similarly, recent studies of the adult human nasal region have documented key differences in nasal form between males and females that are potentially linked to sexual dimorphism in body size, composition, and energetics. To better understand this potential developmental and functional dynamic, we first assessed sexual dimorphism in the nasal cavity in recent humans to determine when during ontogeny male-female differences in nasal cavity size appear. Next, we assessed whether there are significant differences in nasal/body size scaling relationships in males and females during ontogeny. Using a mixed longitudinal sample we collected cephalometric and anthropometric measurements from n = 20 males and n = 18 females from 3.0 to 20.0+ years of age totaling n = 290 observations. We found that males and females exhibit similar nasal size values early in ontogeny and that sexual dimorphism in nasal size appears during adolescence. Moreover, when scaled to body size, males exhibit greater positive allometry in nasal size compared to females. This differs from patterns of sexual dimorphism in overall facial size, which are already present in our earliest age groups. Sexually dimorphic differences in nasal development and scaling mirror patterns of ontogenetic variation in variables associated with oxygen consumption and tissue maintenance. This underscores the importance of considering broader systemic factors in craniofacial development and may have important implications for the study of patters craniofacial evolution in the genus Homo. Copyright © 2013 Wiley Periodicals, Inc

Computer simulations show that Neanderthal facial morphology represents adaptation to cold and high energy demands, but not heavy biting

Three adaptive hypotheses have been forwarded to explain the distinctive Neanderthal face: (i) an improved ability to accommodate high anterior bite forces, (ii) more effective conditioning of cold and/or dry air and, (iii) adaptation to facilitate greater ventilatory demands. We test these hypotheses using three-dimensional models of Neanderthals, modern humans, and a close outgroup (Homo heidelbergensis), applying finite-element analysis (FEA) and computational fluid dynamics (CFD). This is the most comprehensive application of either approach applied to date and the first to include both. FEA reveals few differences between H. heidelbergensis, modern humans, and Neanderthals in their capacities to sustain high anterior tooth loadings. CFD shows that the nasal cavities of Neanderthals and especially modern humans condition air more efficiently than does that of H. heidelbergensis, suggesting that both evolved to better withstand cold and/or dry climates than less derived Homo. We further find that Neanderthals could move considerably more air through the nasal pathway than could H. heidelbergensis or modern humans, consistent with the propositions that, relative to our outgroup Homo, Neanderthal facial morphology evolved to reflect improved capacities to better condition cold, dry air, and, to move greater air volumes in response to higher energetic requirements

Supplementary Material from Computer simulations show that Neanderthal facial morphology represents adaptation to cold and high energy demands, but not heavy biting

Three adaptive hypotheses have been forwarded to explain the distinctive Neanderthal face: (i) an improved ability to accommodate high anterior bite forces, (ii) more effective conditioning of cold and/or dry air, and, (iii) adaptation to facilitate greater ventilatory demands. We test these hypotheses using three-dimensional models of Neanderthals, modern humans, and a close outgroup (<i>H. heidelbergensis</i>), applying finite-element analysis (FEA) and computational fluid dynamics (CFD). This is the most comprehensive application of either approach applied to date and the first to include both. FEA reveals few differences between <i>H. heidelbergensis</i>, modern humans and Neanderthals in their capacities to sustain high anterior tooth loadings. CFD shows that the nasal cavities of Neanderthals and especially modern humans condition air more efficiently than does that of <i>H. heidelbergensis</i>, suggesting that both evolved to better withstand cold and/or dry climates than less derived <i>Homo</i>. We further find that Neanderthals could move considerably more air through the nasal pathway than could <i>H. heidelbergensis</i> or modern humans, consistent with the propositions that, relative to our outgroup <i>Homo</i>, Neanderthal facial morphology evolved to reflect improved capacities to better condition cold, dry air, and, to move greater air volumes in response to higher energetic requirements