Geometric Morphometrics

Geometric morphometrics is a set of methods that employ 2-d or 3-d coordinates of landmarks or semilandmarks as variables (instead of the the more commonly used distance or angle measurements). Landmarks are usually standard osteometric points, which are also used in the definition of traditional osteometric measurements. They should be homologous across specimens. Semilandmarks are used to quantify curves or surfaces.

Coordinate data can be analyzed in a number of ways, but commonly are processed with Procrustes Superimposition. This procedure translates, rotates and scales specimen landmark configurations to unit size. During Procrustes fitting, therefore, size is separated from shape, enabling their separate analysis, as well as the analysis of the relationship between these two aspects of morphology.

Like conventional morphometrics, geometric morphometrics allow statistical inference. However, they present several advantages over the more traditional methods: coordinate data better retain the geometry of the studied objects; they allow the quantification of features that are difficult to measure with convnetional distance measurements; importantly, they allow the intuitive and interactive visualization of morphological differences.

The Paleoanthropology section has a strong focus in applying geometric morphometric methods to questions in paleoanthropology and has extensive facilities to allow researchers and students to learn and use these methodologies. The Paleoanthropology Imaging laboratory is equipped with scanning and digitizing equipment, including a NextEngine laser scanner and a Breuckmann light scanner. Two computer workstations equiped with software for the processing of high volume data are also available.