This project will test the critical assumption held in quantitative genetics that heritable covariation remains stable over evolutionary time. This assumption will be tested by examining the locomotor morphology of three Primate genera, specifically tamarins (Saguinus fuscicollis, Saguinus oedipus), marmosets (Callithrix jacchus) and macaques (Macaca mulatta). With these three genera, the stability of heritable covariation will be examined over short evolutionary time with comparisons among tamarins and marmosets. Patterns will also be examined over long evolutionary time, with tamarins and marmosets compared to macaques. Linear measurements of the appendicular skeleton and girdles will be analyzed to examine covariation of traits between appendages within each species, and within appendages between species. The samples used in this study contain individuals of known family relationship. Mixed-model analytical techniques allows the use of all known relatives in the estimation of the genetic, environmental and phenotypic covariance structure. The study taxa include two arboreal quadrupeds (S. oedipus, C. jacchus), a terrestrial quadruped (C. jacchus) and a primate which frequently locomotes by vertical clinging and leaping (S. fuscicollis). In addition, this study will contrast different phenotypic and locomotor groups to provide insight into the evolution of primate locomotor morphology.
