Summary: Phenotypic Covariance Structure in Tamarins (Genus
Saguinus): A Comparison of Variation Patterns Using Matrix
Correlation and Common Principal Component Analysis
REBECCA ROGERS ACKERMANN AND JAMES M. CHEVERUD*
Department of Anatomy and Neurobiology, Washington University School
of Medicine, St. Louis, Missouri 63110
KEY WORDS cranial morphology; Callitrichidae; variability;
quantitative methods
ABSTRACT Constancy of variation/covariation structure among popula-
tions is frequently assumed in order to measure the differential selective
forces which have caused population differentiation through evolutionary
time. Following Steppan ([1997] Evolution 51:571­594), this assumption is
examined among closely related tamarin species (genus Saguinus), using two
distinct approaches applied to the task of evaluating similarity in patterns of
morphological variation: common principal component analysis and matrix
correlations. While the results of these analyses may appear contradictory,
closer examination reveals them as complementary, highlighting the wisdom
of combined methodologies. Overall, the results reveal a close relationship
among the morphologically based variance structures of the tamarin species
a relationship whose pattern is consistent with the pattern of phylogenetic

Source: Ackermann, Rebecca Rogers - Department of Archaeology, University of Cape Town
Cheverud, James M. - Department of Anatomy and Neurobiology, Washington University in St. Louis

Collections: Biology and Medicine