3. Morphology
Craniodental linear measurements were taken using digital
calipers and recorded to the nearest tenth of a millimeter (Tables
S3, S4). In addition to standard caliper measurements, we used 3-
D geometric morphometric techniques to compare cranial shape
of C. lomamiensis and C. hamlyni. The 23 landmarks chosen to
capture the overall shape of the cranium are listed in Table S5 and
include Type 1, Type 2, and Type 3 landmarks [6]; these
landmarks included those used by Fleagle et al. [7] in their larger
study of primate cranial diversity, and additional cranial landmarks
deemed to be repeatable and informative.
We digitized the landmarks on each cranium using a Microscribe
G2X digitizer (Immersion Corp). The individual crania
were immobilized in a bed of Play-Doh, and the landmarks were
digitized in two sets–one superior view and one inferior view. All
bilateral landmarks were digitized on the right side of the cranium.
As reference points, five landmarks were digitized in both views.
Subsequently, the two sets of landmarks were combined using the
program DVLR v. 0.4.9 [8] to obtain a single set of 23 threedimensional
coordinates for each cranium. We imported the
landmark data into the software package Morphologika [9], and
performed a Procrustes superimposition analysis on the entire
sample of C. lomamiensis (n= 3) and C. hamlyni (n= 7) crania. We
then used a principal components analysis (PCA) of the Procrustes
superimposition to identify the major axes of cranial shape among
all of the crania. Pelage and skin coloration are described using
standard color references [10].