Biology Reference
In-Depth Information
FIGURE 2.11
Landmarks for a three-dimensional analysis of marmot skull shape. (A) A marmot skull; (B) the
configuration of three-dimensional landmarks.
function; motivating studies of mandibular shape are questions about the evolutionary
relationships between mandibular form, function and ecology and about the discrepancies
between morphological and biomechanical disparity (e.g.
Velhagen and Roth, 1997;
Caumul and Polly, 2005; Barrow and Macleod, 2008; Michaux et al., 2008; Perez et al., 2009;
Swiderski and Zelditch, 2010
).
The mandible is not only interesting from a variety of biological perspectives, it is also
apparently quite simple to analyze, being a single bone that is nearly two-dimensional.
However, as may already be evident from comments about mandibular landmarks
earlier in this chapter, the mandible lacks landmarks where they are most needed. In the
case of studies of mandibular function, the lack is most significant in the regions where
muscles insert. For studies of integration and modularity, the lack is more widespread;
such studies assess the covariances within hypothesized modules relative to covariance
between them. Thus, every module needs to be sampled densely enough to be able to
