Introduction - An Invariant Approach to Statistical Analysis of Shapes - page 11

Figure 1.3 Adult Cebus apella skull with the location of 6 facial landmarks shown.
These landmarks are homologous to those plotted on the adult Macaca fascicularis skull
in Figure 1.2. Landmarks shown include: 1, nasale; 2, intradentale superior; 3, premax-
illary-maxillary junction; 4, zygomaxillare superior; 5, maxillary tuberosity; 6, posterior
nasal spine (located on the sagittal plane).
Smithsonian Institution, were aged according to dental eruption pat-
terns (Richtsmeier and Cheverud et al., 1993). Landmarks were digi-
tized directly from the external surface of the face, neurocranium, and
cranial base of these skulls using the 3Space digitizer (see Chapter 2 ).
Landmarks used in this topic represent a subset of the available facial
landmarks ( Figure 1.2 ) .
In addition to the landmark data collected from a large collection of
skulls of Macaca fascicularis, we have a comparable data set collected
from skulls of Cebus apella , the capuchin monkey (Corner and
Richtsmeier, 1991) ( Figure 1.3 ) . These species are members of differing
infraorders of the suborder Anthropoidea . The split between the New
World monkeys (Infraorder: platyrrhini, of which Cebus apella is a
member) and the Old World monkeys (Infraorder: catarrhini, of which
Macaca fascicularis is a member) dates to a time before the Oligocene.
Beyond the geographic separation that has been maintained over mil-
lions of years, New World monkeys differ from Old World monkeys in
many respects including, but not limited to social structure, overall
body size, and craniofacial features.
These data sets enable us to look specifically at differences in