Biology Reference
In-Depth Information
for
McKeown (2000)
. Here, three-dimensional coordinates from 22 facial landmarks for eight
samples from sites associated with the Arikara of the Middle Missouri region of South
Dakota are analyzed using geometric morphometrics and traditional statistical methods.
The landmarks employed in this study are depicted in
Figure 12.7
. The samples are from sites
along the Missouri River and vary temporally and geographically as shown in
Figure 12.8
.
The temporal and cultural period assignments for the various components are drawn from
Jantz (1997)
and
McKeown (2000)
.
In this example, three-dimensional coordinates observed on crania from each site compo-
nent are analyzed in order to explore the pattern of morphological variation that exists
among individuals from these sites. A three-dimensional digitizer and the program 3Skull
were used to record the coordinate data. The coordinate-based configurations were subjected
to a generalized Procrustes analysis (GPA) using MorphoJ (
Klingenberg, 2011
), which
accounts for the effects of object symmetry, which means the structure is symmetric in itself
and has an interior line or plane, so that its left and right halves are mirror images of each
other, such as the vertebrate skull (
Klingenberg et al., 2002
).
Since crania have object symmetry and numerous bilateral landmarks are included in the
dataset, it is useful to only analyze the symmetric component of the morphological variation
(leaving out the intra-individual asymmetric component). MorphoJ partitions these two
components, permitting the analysis of
the symmetric component alone, making it
FIGURE 12.7
Landmarks used in the biological distance analysis case study.
