title: Ontogenetic and static allometry in the human face: contrasting Khoisan and Inuit.
abstract: OBJECTIVE
  Regional differences in modern human facial features are present at birth, and ontogenetic allometry contributes to variation in adults. However, details regarding differential rates of growth and timing among regional groups are lacking. We explore ontogenetic and static allometry in a cross-sectional sample spanning Africa, Europe and North America, and evaluate tempo and mode in two regional groups with very different adult facial morphology, the Khoisan and Inuit.
  
  
  METHODS
  Semilandmark geometric morphometric methods, multivariate statistics and growth simulations were used to quantify and compare patterns of facial growth and development.
  
  
  RESULTS
  Regional-specific facial morphology develops early in ontogeny. The Inuit has the most distinct morphology and exhibits heterochronic differences in development compared to other regional groups. Allometric patterns differ during early postnatal development, when significant increases in size are coupled with large amounts of shape changes. All regional groups share a common adult static allometric trajectory, which can be attributed to sexual dimorphism, and the corresponding allometric shape changes resemble developmental patterns during later ontogeny.
  
  
  CONCLUSIONS
  The amount and pattern of growth and development may not be shared between regional groups, indicating that a certain degree of flexibility is allowed for in order to achieve adult size. In early postnatal development the face is less constrained compared to other parts of the cranium allowing for greater evolvability. The early development of region-specific facial features combined with heterochronic differences in timing or rate of growth, reflected in differences in facial size, suggest different patterns of postnatal growth.
authors.affiliation: Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig, 04103, Germany.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Freidline
authors.affiliation: Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig, 04103, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Gunz
authors.affiliation: Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig, 04103, Germany.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Hublin
mesh_terms: D000293:Adolescent; D000328:Adult; D000885:Anthropology, Physical; D000886:Anthropometry / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005145:Face / Q000033:anatomy & histology*; D005147:Facial Bones / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008297:Male; D025341:Principal Component Analysis; D044469:Racial Groups / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: Inuit; Khoisan; Point Hope; heterochrony; midface; ontogenetic allometry; semilandmark geometric morphometrics; static allometry